Mizzau and TNT Australia Pty Ltd (Compensation)

This matter concerned an appeal by Mr Mizzau against a decision by TNT Australia Pty Ltd to deny him workers' compensation. Mr Mizzau claimed he suffered an exacerbation of social anxiety disorder and depression due to his employment. The dispute centred on whether the ailment or its aggravation was contributed to to a significant degree by his employment, and crucially, whether it resulted from reasonable administrative action taken in a reasonable manner.

The court was required to determine if Mr Mizzau had suffered an injury as defined by the *Safety, Rehabilitation and Compensation Act 1988* (Cth). This involved assessing whether his social anxiety disorder and depression constituted a disease or an aggravation of a pre-existing condition, and if so, whether his employment was a significant contributing factor. A key legal issue was whether the administrative actions taken by his employer, specifically the handling of performance management and a meeting, constituted "reasonable administrative action taken in a reasonable manner," which would exclude the claim from compensation.

The court found that Mr Mizzau did suffer an exacerbation of a longstanding social anxiety disorder with developing depression, and that his employment contributed to this to a significant degree. The court determined that the administrative action taken by the Respondent, particularly the refusal to postpone a meeting to allow his preferred support person to attend and his subsequent placement on a performance improvement plan, was not taken in a reasonable manner. Therefore, the exclusion for reasonable administrative action did not apply. The court applied the principles from *Comcare v Martin*, which clarified that an employee suffers a disease as a result of administrative action if that action is a cause in fact of the disease, and that the administrative action need not be the sole cause.

The reviewable decision of TNT Australia Pty Ltd was set aside. In substitution, it was decided that TNT Australia Pty Ltd is liable to pay compensation to Mr Mizzau in respect of the injury, being the exacerbation of social anxiety disorder and depression, deemed to have been sustained by him on 21 September 2015. Comcare was ordered to pay the costs incurred by Mr Mizzau in these proceedings unless an application for directions regarding costs was made within fourteen days.