Prasad v Accident Compensation Corporation
[2025] NZHC 3371
•6 November 2025
IN THE HIGH COURT OF NEW ZEALAND AUCKLAND REGISTRY
I TE KŌTI MATUA O AOTEAROA TĀMAKI MAKAURAU ROHE
CIV-2025-404-000513 [2025] NZHC 3371
UNDER the Accident Compensation Act 2001 IN THE MATTER OF
a special leave application pursuant to s 162 of the Act
BETWEEN
SATEND PRASAD
Applicant
AND
ACCIDENT COMPENSATION CORPORATION
Respondent
Hearing: 11 June 2025 Appearances:
M Edison for the Applicant F Becroft for the Respondent
Judgment:
6 November 2025
JUDGMENT OF GARDINER J
This judgment was delivered by me on 6 November 2025 at 4.00 pm pursuant to Rule 11.5 of the High Court Rules
Registrar/Deputy Registrar
Solicitors:
Edison Tam Lawyers, Auckland Medico Law Limited, Auckland
PRASAD v ACCIDENT COMPENSATION CORPORATION [2025] NZHC 3371 [6 November 2025]
Introduction
[1] Satend Prasad worked as a welder/fitter and fitter/machinist for many years. He made a claim for cover for left glenohumeral osteoarthritis as a work-related gradual process injury. In a series of decisions, the Accident Compensation Corporation (ACC) declined cover based on medical evidence that the condition was not work-related. The third and final refusal decision was upheld on independent review. The review decision was then upheld by Judge A A Sinclair.1 Judge D L Henare declined leave to appeal to this Court.2
[2]Mr Prasad now seeks special leave to appeal the decision of Judge Sinclair.
[3]ACC opposes the application.
[4]This application requires me to decide the following issues:
(a)Is it reasonably arguable that the Judge made an error of law when determining causation according to s 30(2) of the Accident Compensation Act 2001 (the Act)?
(b)Is it reasonably arguable that the Judge made an error of law when applying the “significantly greater risk test” under s 30(2A) of the Act?
(c)In all the circumstances, ought special leave to appeal be granted?
Background
Procedural history
[5] On 22 May 2019, Mr Prasad reported a shoulder sprain resulting from lifting a heavy wet pin at work. ACC granted cover for this incident.
[6] Mr Prasad pursued treatment for the injury but his symptoms persisted. A CT scan of Mr Prasad’s left shoulder identified severe arthrosis in the left glenohumeral
1 Prasad v Accident Compensation Corporation [2024] NZACC 182.
2 Prasad v Accident Compensation Corporation [2025] NZACC 34.
joint. This led to discussions of surgery with an orthopaedic surgeon, Craig Bell. Accordingly, he sought cover for this.
[7] On 30 April 2021, ACC declined cover as the osteoarthritis was merely an underlying condition made apparent by Mr Prasad’s shoulder sprain.
[8] Mr Prasad then lodged a Work-Related Gradual Process Injury (WRGPI) claim. Again, ACC declined, on the basis of medical opinion from Dr Chris Walls and Dr John Monigatti.
[9] Mr Prasad applied for a review of the decision. The Reviewer quashed the decision and directed that a worksite assessment be obtained and Mr Prasad be referred for an independent medical assessment, following which a new cover decision would be issued. The opinion of Dr David Payne, a specialist occupational and environmental physician, was produced.
[10] On 9 June 2023, ACC issued a further decision declining cover for a WRGPI. This decision was upheld in a review decision dated 11 October 2023.
District Court decisions
[11] Mr Prasad appealed the October 2023 review decision to the District Court. In support, he provided the opinion of Dr David Black.
[12] Judge Sinclair upheld the review decision, finding that the weight of the evidence did not support Mr Prasad’s work tasks as causing or contributing to the cause of his osteoarthritis. She preferred the medical evidence relied on by ACC in all respects, particularly noting Dr Payne’s comprehensive review of the literature with respect to shoulder arthritis.
[13] Although the claim failed at causation, the Judge considered it helpful to address the second issue of the significantly greater test. The Judge first noted that Dr Black’s opinion was informed by Mr Prasad’s personal circumstances (such as a predisposition to shoulder injury) instead of the more general, comparative analysis required by the significantly greater risk test. The Judge also referred to
Dr Monigatti’s criticism of Dr Black’s “impartial and verifiable evidence” as lacking, as Dr Black wrongly inferred increased risk from one case (Mr Prasad’s). Accordingly, the Judge concluded that the risk of suffering glenohumeral osteoarthrosis is not significantly greater for persons who perform the employment tasks undertaken by Mr Prasad than persons who do not perform them.
[14] Judge Henare declined leave to appeal on the basis Judge Sinclair’s conclusions were open to her on the evidence.
Legal Principles
Leave to appeal
[15]Section 162 of the Act reads:
162 Appeal to High Court on question of law
(1)A party to an appeal who is dissatisfied with the decision of a District Court as being wrong in law may, with the leave of the District Court, appeal to the High Court.
(2)The leave of the District Court must be sought within 21 days after the District Court’s decision.
(3)If the District Court refuses to grant leave, the High Court may grant special leave to appeal.
(4)The special leave of the High Court must be sought within 21 days after the District Court refused leave.
(5)The High Court Rules and sections 74 to 78 of the District Courts Act 1947, with all necessary modifications, apply to an appeal under this section as if it were an appeal under section 72 of that Act.
[16] An appeal may be made to this Court on a question of law. Leave will not be granted for an error of fact “dressed up” as an error of law. However, a mixed question of law and fact is a matter of law. The decision-maker’s treatment of facts may amount to an error of law where there is no evidence to support the decision, the evidence is inconsistent with and contradictory of the decision, or the true and only reasonable conclusion on the evidence contradicts that result. Whether a statutory provision has
been correctly interpreted and applied to the facts is a question of law. The Court of Appeal has said that the issue of causation is a mixed question of law and fact.3
[17] The point of law must be capable of bona fide and serious argument. Leave is not granted as a matter of course. On a second appeal, an appellate court’s function is to clarify the law and determine whether it has been properly interpreted and applied. The focus is on whether the question of law is worthy of consideration. In Kenyon v Accident Compensation Corporation, this Court emphasised that a proposed appeal should be deserving of scarce judicial time, have an issue of principle at stake, and have a reasonable prospect of success.4 Where leave has been refused by the District Court, there will normally have to be some extraordinary factor which has not been taken into account.
Work-related gradual process injuries
[18] Section 20 of the Act provides that a person is covered for a personal injury if it is one of the defined categories of injury set out in s 20(2), including:
(e)personal injury caused by work-related gradual process, disease, or infection suffered by a person:
[19] Section 26(1) defines personal injury in several ways, including a “physical injury suffered by a person including, for example, a strain or a sprain”. However, s 26(4) excludes from that definition personal injury “caused wholly or substantially by the ageing process”.
[20] Section 30 (as in force at the relevant time) further defines personal injury caused by a work-related gradual process in circumstances described in subss (2)– (2A):
(2)The circumstances are—
(a)the person—
(i)performs an employment task that has a particular property or characteristic; or
3 Accident Compensation Corporation v Ambros [2007] NZCA 304, [2008] 1 NZLR 340 at [24].
4 Kenyon v Accident Compensation Corporation [2002] NZAR 385 (HC) at [15].
(ii)is employed in an environment that has a particular property or characteristic; and
(b)the particular property or characteristic—
(i)causes, or contributes to the cause of, the personal injury; and
(ii)[Repealed]
(iii)may or may not be present throughout the whole of the person’s employment; and
(c)that, if the particular property or characteristic is present in both the person’s employment tasks or environment and non- employment activities or environment, it is more likely that the person’s personal injury was caused as a result of the employment tasks or environment rather than the non- employment activities or environment.
(2A) However, even if it is established that a claimant’s personal injury was caused in the circumstances described in subsection (2), the Corporation may decline the claim if the Corporation establishes that the risk of suffering the personal injury is not significantly greater for persons who—
(a)perform the employment task than it is for persons who do not perform it; or
(b)are employed in that type of environment than it is for persons who are not.
Is it reasonably arguable that the Judge made an error of law when determining causation according to s 30(2) of the Act?
[21] The first alleged error of law is that the Judge was wrong to conclude that Mr Prasad’s work tasks did not cause or contribute to the cause of his personal injury, as required by s 30(2) of the Act.
Submissions for Mr Prasad
[22] Mr Prasad raises three issues. First, he alleges that the Judge failed to apply the correct test for causation pursuant to s 30(2)(b)(i) of the Act. Mr Edison submits that the Judge relied on the “consensus opinion” of the three experts for ACC and failed to consider whether a causal contribution could be inferred based on all the evidence. Mr Edison relies on the Court of Appeal’s comments in Ambros that the Court’s assessment of causation could differ from expert opinion and can infer
causation in circumstances where the medical experts cannot. Further, the only time that a Judge cannot draw a robust inference of causation is where medical science says there is no possible connection between the events and the injury.5 Mr Edison submits that the medical evidence on which ACC relied was well short of proving no possible connection between Mr Prasad’s work tasks and his injury.
[23] Second, that the Judge failed to properly analyse or understand the expert medical evidence in reaching her conclusions on causation. The Judge accepted that Mr Prasad likely suffered a shoulder injury many years ago, which predisposed him to accelerated degenerative changes. Dr Walls found that trauma is a recognised occupational cause of glenohumeral osteoarthritis, and the work tasks would have been an aggravating factor. Following on from this, the Judge found that, while the work tasks would have been an aggravating factor, that was not sufficient to establish causation. Mr Edison submits that this is contrary to Taylor v ACC and an error.6
[24] The third issue raised by Mr Edison is the Judge’s reliance on Dr Payne’s evidence “in all respects”. Drs Payne and Black are both experienced occupational medical specialists. Yet the Judge did not explicitly evaluate Dr Black’s evidence or explain why it was not preferred over Dr Payne (or given any weight). On that basis, the decision failed to give rational reasons amounting to a breach of natural justice.
Submissions for ACC
[25] Ms Becroft disputes that the Judge applied the correct legal test. The Judge clearly and expressly acknowledged, with reference to the relevant authorities, that a causal contribution suffices. The Judge’s focus (properly) was on whether the weight of the evidence supported causation.
[26] Ms Becroft first notes that the applicant’s submissions represent a revival of an argument on the facts, which is not an appropriate exercise in a special leave setting. Nevertheless, Ms Becroft submits that the Judge’s findings were open to her because
5 Accident Compensation Corporation v Ambros, above n 3.
6 Taylor v Accident Compensation Corporation [2013] NZACC 359 at [29]–[30].
there was clear evidence which showed Mr Prasad’s work did not cause, or contribute to the cause, of the glenohumeral osteoarthritis.
[27] Responding to the submission regarding the lack of real consensus between the experts, Ms Becroft says that the three doctors’ opinions were united in all material respects. And the Judge was entitled to rely on the three largely concurring opinions.
[28] Ms Becroft also disputes that the Judge failed to have regard to Dr Black’s evidence. This was set out in detail by the Judge in reaching her conclusion.
Analysis
[29] I consider that the Judge did arguably make an error of law when assessing causation. The Judge appears to have reached the conclusion that Mr Prasad’s work tasks did not cause or contribute to the cause of his glenohumeral osteoarthritis based on there being a consensus amongst the senior occupational physicians (Drs Walls, Payne and Monigatti) to that effect. Yet arguably, there was not a consensus that Mr Prasad’s work tasks had not contributed to the cause of his injury.
[30] The Judge relied heavily on the opinions of Drs Walls and Payne. But Dr Walls did not actually conclude that Mr Prasad’s work tasks did not cause or contribute to the cause of his glenohumeral osteoarthritis.
[31] In his first report, Dr Walls observed that the work factors leading to an increased incident of glenohumeral osteoarthritis were not “well described”. Dr Walls said that “one is forced to consider more general factors” such as heavy work, highly repetitive upper limb activities and/or sustained or repeated shoulder postures of more than 60 degrees flexion or abduction. Dr Walls concluded that work as a machine fitter is not likely to lead to a gradual process injury, because although the role contains some episodes of these factors, it is not highly repetitive as a mono activity, and nor are there prolonged and repetitive periods of working in more than 60 degrees flexion. The Judge recorded that Dr Walls went on to speculate whether Mr Prasad had suffered a childhood shoulder dislocation, observing that a Bankart lesion suggested a previous dislocation. Dr Walls then opined that Mr Prasad’s heavy work through his working life had aggravated the changes brought about by the original injury.
[32] In his second report, Dr Walls repeated his opinion that the glenohumeral osteoarthritis was initiated by a childhood shoulder dislocation and then aggravated by age, daily living and Mr Prasad’s work as a fitter engineer over many years. He concluded that, although Mr Prasad’s work exposures were not the major or significant contributor to his left shoulder osteoarthritis, they were an aggravating factor.
[33] Dr Walls’s opinion that Mr Prasad’s work tasks were unlikely to lead to a gradual process injury appears to have been based on an incorrect understanding of what his work involved. His assessment predated the functional job description conducted by Ms McEntee, Occupational Therapist, at the direction of the Reviewer. Ms McEntee concluded that Mr Prasad’s role as a fitter machinist fell predominantly into the “very heavy work” category, with 70 per cent of the work occurring between the waist and overhead and a “constant” requirement to lift materials between 10 kg to 30 kg.
[34] In any event, despite this part of his opinion, Dr Walls concluded that Mr Prasad’s work tasks over many years contributed to him developing glenohumeral osteoarthritis by aggravating the damage caused by his childhood injury. While a doctor may not consider an aggravating factor to be a cause, the test under s 30(2)(b)(i) is whether the work tasks have caused or contributed to the cause. It is well-settled that the Act only requires that the particular work task contribute to the cause of the personal injury — it need not be the sole cause.7
[35] Dr Payne reviewed Mr Prasad’s occupational history and history of shoulder pain, as well as carrying out a physical examination. He observed Mr Prasad carrying out his workplace tasks. He also undertook a literature review relating to shoulder arthritis. He noted that age is a recognised factor in glenohumeral osteoarthritis, as is obesity. Additionally, heavy construction work and overhead sports have been identified as risk factors. He noted a study that found evidence that overhead working, heavy lifting and working in an awkward posture increase the risk of shoulder disorders generally but not specifically osteoarthritis. He then said:
7 Cullen v Accident Compensation Corporation [2001] NZAR 641 (DC) at [25]; and Hansen v Accident Compensation Corporation [2003] NZACC 71 at [18]–[19].
Therefore, when answering question 4 were there any employment properties or characteristics that caused or contributed to the client’s conditions? I note the significant volume of literature, with no real cohesive theme or consistency amongst the literat[ure]. It follows therefore that my only answer to this question can be no - there are no employment properties or characteristics that cause or contributed to Mr Prasad’s condition.
[36] It appears therefore that Dr Payne’s opinion that there were no work tasks that caused or contributed to Mr Prasad’s glenohumeral osteoarthritis was based on there being a lack of literature confirming that work tasks of the kind performed by Mr Prasad was a cause or contributing cause of the condition.
[37] It follows that the Judge arguably erred when concluding that there was a consensus between the senior physicians that Mr Prasad’s work tasks did not cause or contribute to the cause of his glenohumeral osteoarthritis. Dr Walls considered that Mr Prasad’s work tasks were an aggravating factor. Dr Payne’s opinion arguably stopped short of reaching a definitive conclusion on the issue.
[38] Furthermore, the Judge seems to have treated the physicians’ opinions on causation as definitive. The Judge did not overtly consider the evidence of the physicians in the context of all the circumstances and assess whether as a matter of law, a causal contribution could be inferred. Relevant circumstances include:
(a)Mr Prasad’s relatively young age, that he worked for around 30 years in roles that involved heavy lifting (constant lifting, according to Ms McEntee), and working at head height and overhead height.
(b)The early opinion of Mr Ball, an orthopaedic surgeon, that Mr Prasad’s work “obviously will not be helping either and it may well be a factor in the etiology of his arthritis”.
(c)That Dr Walls considered that Mr Prasad’s work had been an aggravating cause.
(d)That Drs Payne and Monigatti’s conclusions on causation were primarily based on there being no clear body of evidence in the
literature linking the physical characteristics of heavy work to the development of glenohumeral osteoarthritis.
Is it reasonably arguable that the Judge made an error of law when applying the “significantly greater risk test” under s 30(2A) of the Act?
Submissions for Mr Prasad
[39] Mr Prasad also alleges the Judge erred in concluding that ACC established the risk of suffering the shoulder injury was not significantly greater for persons performing Mr Prasad’s employment tasks than for persons who do not perform them, pursuant to s 30(2A) of the Act.
[40] Mr Edison submits that the Judge did not have reasonable grounds to disregard Dr Black’s evidence on this aspect of the test. The Judge criticised Dr Black for not referring to any epidemiological evidence to substantiate his opinion, when he could not do so as the literature was silent. The Judge found that Dr Black’s opinion was informed by his conclusion on causation despite his reference to the objective test. In fact, Dr Black reached his conclusion based on analysis of a task involving positioning a heavy pin into a lathe chuck, commenting that task is very challenging and “in the presence of pre-existing arthropathy would be very likely to accelerate degenerative change”.
[41] Furthermore, the Judge erred in law by relying on a lack of epidemiological evidence for her conclusion that the risk of suffering personal injury was not significantly greater as defined in s 30(2A). An absence of studies cannot amount to positive evidence that Mr Prasad was not at significantly greater risk of injury and cannot satisfy the onus of proof.
Submissions for ACC
[42] Ms Becroft accepts that a lack of research is not in itself determinative. However, the Judge was entitled to reach her conclusion based on the experts’ interpretation of the implications of that lack of research. Mr Edison’s submission appears to suggest that ACC is required to provide epidemiological evidence ruling out a significantly greater risk which is not the case. What the Act requires is ACC to
be satisfied that the risk of injury is not significantly greater for persons who perform the employment tasks than persons who do not. The evidence from the three specialists enabled it not to be satisfied.
Analysis
[43] In my view, it is arguable that the Judge erred in her application of a 30(2A). The Judge concluded:
Dr Payne undertook a careful review of the literature and was satisfied that there were no studies demonstrating that there is a significantly greater risk of glenohumeral osteoarthritis for persons performing Mr Prasad’s employment tasks than for persons who do not. Having reached his view on causation, Dr Walls did not consider that there was any significantly greater risk. Dr Monigatti agreed and also noted the absence of any supporting literature. I accept the evidence of these three senior Occupational Medicine Specialists.
The significantly greater risk test is an objective one. I have no difficulty in concluding that there is sufficient evidence before the Court to enable me to be satisfied that the risk of suffering glenohumeral osteoarthrosis is not significantly greater for persons who perform the employment tasks undertaken by Mr Prasad than persons who do not perform them.
[44] The Judge found that people performing Mr Prasad’s work tasks were at no greater risk of developing osteoarthritis on the basis of the opinions of the three physicians. But Dr Monigatti’s evidence was only that:
… there was no clear body of evidence in the literature that links the physical characteristics of even very heavy work to the development of glenohumeral osteoarthrosis or points to a significantly increased risk of it occurring in welders/fitters/machinists or any other occupational group.
[45] Similarly, Dr Payne’s opinion was only that a significantly greater risk was not demonstrated in the literature:
This [significantly greater risk] has not been demonstrated in the literature. I note the tennis study discussed above showing that there was a significantly increased risk of shoulder arthritis however this was limited to the dominant side. I also note the two main issues with the study is that the players/workers with arthritis were not only older (putting forward age as the primary driver for the cause) but also the fact that this is a very small sample study.
Therefore, when considering the literature, I have not been able to find any evidence that there is a significantly greater risk for shoulder arthritis and those who perform the employment task (or similar tasks) than those who do not perform it.
[46] The onus is on ACC to establish that the risk of suffering the personal injury is not significantly greater for people undertaking the work tasks. There is merit to the argument that ACC does not meet this onus by pointing to an absence of evidence demonstrating a significantly greater risk. Arguably, that is as far as the physicians’ opinions went. Arguably then, the Judge erred by finding that ACC had discharged the onus on it to positively establish that there was no significantly greater risk in reliance on the medical opinions, when the opinions did not go that far.
Should special leave be granted?
[47] The points raised on appeal are capable of serious argument. In my view, the proposed appeal is worthy of consideration and scarce judicial resources given the potential errors in Mr Prasad’s first appeal and the significance of the outcome to him. These considerations outweigh the interest in the finality of litigation. Fundamentally, I consider that it is in the interests of justice for Mr Prasad to advance his appeal.
Result
[48]The application for leave to appeal is granted.
[49] Mr Prasad has been successful in this application. In view of his personal circumstances, rather than reserve costs, I award him 2B costs and reasonable disbursements.
Gardiner J
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