Commerce Commission v Winstone Wallboards Limited - [2025] NZHC 2695

IN THE HIGH COURT OF NEW ZEALAND AUCKLAND REGISTRY

I TE KŌTI MATUA O AOTEAROA TĀMAKI MAKAURAU ROHE

COMMERCIAL PANEL

CIV-2024-404-2853

[2025] NZHC 2695

UNDER ss 27, 36 and 80 of the Commerce Act 1986

BETWEEN

COMMERCE COMMISSION

Plaintiff

AND

WINSTONE WALLBOARDS LIMITED

Defendant

Hearing: 9 September 2025

Appearances:

M D O’Brien KC, B Hamlin and E M Greig for plaintiff

J D Every-Palmer KC, A M Boberg and T C Wood for defendant

Date of judgment:

17 September 2025

JUDGMENT OF JAGOSE J

[Tailored discovery]

This judgment was delivered by me on 17 September 2025 at 3.30pm.
Pursuant to Rule 11.5 of the High Court Rules.

………………………… Registrar/Deputy Registrar

Counsel/Solicitors:
M D O’Brien KC, Auckland
J D Every-Palmer KC, Wellington B Hamlin, Barrister, Wellington Meredith Connell, Auckland
Bell Gully, Auckland

COMMERCE COMMISSION v WINSTONE WALLBOARDS LTD [2025] NZHC 2695 [17 September 2025]

[1] For my decision is Winstone’s application for tailored discovery of “internally created … documents and communications produced by or for” either of two specified deliberative groups constituted within the Commission in relation to (a) its 2013–2014 and 2022–2024 investigations into Winstone and (b) its 2021–2022 competition study so far as it related to the market for plasterboard in New Zealand and Winstone’s practices.

Background

[2] By claim dated 31 October 2024, the Commission seeks declarations and pecuniary penalties on its allegations, between 1 April 2016 and 31 December 2022, Winstone entered into and gave effect to plasterboard supply arrangements with major building supply merchants to substantially lessen competition in a market in contravention of s 27, and otherwise took advantage of its substantial degree of power in a market for anti-competitive purpose in contravention of s 36, of the Commerce Act 1986. So far as the s 27 allegations are concerned, they mainly are focused on rebates provided by Winstone to merchants as part of the plasterboard supply arrangements. The s 36 allegations plead particular conduct by which Winstone is said to have taken non-specific advantage of its substantial market power to detriment competing plasterboard suppliers.

[3] Winstone denies any contravention but also affirmatively pleads (albeit without particulars, while criticising the Commission for its as-anodyne denial) the Commission’s claims for pecuniary penalties under s 80 are time-barred. Section 80(5) provides:

Proceedings under this section may be commenced within 3 years after the matter giving rise to the contravention was discovered or ought reasonably to have been discovered. However, no proceedings under this section may be commenced 10 years or more after the matter giving rise to the contravention.

‘Discovered’ in this context means “known”.1

1 Commerce Commission v Carter Holt Harvey Ltd [2009] NZSC 120, [2010] 1 NZLR 379 at [29] (in relation to discoverability of loss or damage in terms of s 43(5) of the Fair Trading Act 1986).

[4] The Commission will contend it discovered (or came to know of) the matters giving rise to those alleged contraventions in the course of a competition study it was required by the Minister to carry…

Grounds of appeal

[14] The appellant contends that the primary judge erred in finding that the respondent had discharged the onus of establishing the matters required under the relevant provision.

[15] It was submitted that his Honour failed to give adequate weight to the evidence of the second witness, and that the findings of fact were not reasonably open on the material before the Court.

[16] The respondent, for its part, submits that no error is disclosed, and that the conclusions reached were well within the range of outcomes available to the primary judge.

Consideration

[17] It is convenient to deal first with the question of construction, as the resolution of that issue informs the remaining grounds advanced by the appellant.

[18] For the reasons that follow, we are of the view that the appeal should be allowed in part and the matter remitted for further determination.

Keep reading for free

Create a free CaseChat account to read Commerce Commission v Winstone Wallboards Limited and more:

Read every judgment in full
Ask AI and get answers linked to paragraphs
See how each paragraph was cited in later cases
Download judgments as PDF or Word

Continue with Google

One click creates your free account or signs you in.

By continuing you agree to the Terms and Privacy Policy.

Details

Case: [2025] NZHC 2695
Decision Date: 17 September 2025

CaseChat Overview and Summary

The High Court of New Zealand was presented with an application by Winstone Wallboards Limited for tailored discovery against the Commerce Commission. The Commission had initiated proceedings alleging that Winstone engaged in anti-competitive practices, including entering into plasterboard supply arrangements with major building supply merchants to substantially lessen competition. Winstone sought tailored discovery of specific documents related to the Commission's investigations and studies concerning Winstone and the plasterboard market. The court was tasked with determining whether the proposed tailored discovery was warranted and proportionate to the subject matter of the proceeding.

The primary legal issue was whether the tailored discovery sought by Winstone was necessary and proportionate given the context of the proceeding. The court considered whether the interests of justice required more or less discovery than standard discovery, as permitted under Rule 8.8 of the High Court Rules 2016. The court examined the scope of the agreed and unagreed categories of tailored discovery, particularly focusing on the documents produced by or for the deliberative groups within the Commission that originated facts relating to Winstone and plasterboard. The court needed to ensure that the tailored discovery was not unduly onerous while being reasonably necessary for the purposes of the proceeding.

The court concluded that the tailored discovery sought by Winstone was proportionate to what was at stake and reasonably necessary for the proceeding. The court found that the inclusion of documents that originated facts relating to plasterboard and Winstone, produced by or for the specified deliberative groups within the Commission, was justified. Such documents, if they exist, may be initially recorded in internal Commission documents obtained during the desktop review or from accessible databases. The court decided that the proposed tailored discovery, with the specified inclusion, was appropriate and should be included in the agreed tailored discovery order. The court invited counsel to propose any formal wording necessary to capture the inclusion within the order. Regarding costs, the court indicated that they should lie where they fell, but reserved the right to determine costs if either party disagreed and could not otherwise reach an agreement.

In summary, the High Court of New Zealand granted Winstone Wallboards Limited's application for tailored discovery to the extent that it included documents produced by or for the specified deliberative groups within the Commerce Commission that originated facts relating to plasterboard and Winstone. The court ensured that the tailored discovery was proportionate and reasonably necessary for the proceeding, while also considering the burden on the parties.

Orders