The Trans-Tasman Proceedings Regime and Extraterritorial Subpoenas

By Jack Wass (Stout Street Chambers)

In the recent decision of Sunnya Pty Ltd v Mega Aqua Limited [2025] NZHC 3482, the High Court was asked to grant an order directing a New Zealand company and its New Zealand-resident director to comply with an Australian subpoena that had been issued in contempt proceedings pending in the New South Wales Supreme Court. The case is one of a developing line of decisions demonstrating the courts’ willingness to give full effect to the regime for cooperation in civil proceedings between Australia and New Zealand, and also casts light on wider issues concerning cross-border contempt.

Sections 163-167 of the Evidence Act 2006 provide for the service and enforcement, in New Zealand, of subpoenas issued by Australian courts. These provisions were originally introduced in 1994 to implement the Closer Economic Relations policy, and were a precursor to the broader reform of the Trans-Tasman Proceedings Act 2010 which fundamentally restructured the way the courts of the two countries approach cross-border proceedings (and extended the power to grant cross-border subpoenas to criminal and some family proceedings).

The narrow point taken by the respondent in opposition in Sunnya was that the New Zealand High Court had no jurisdiction to order compliance, because s 165 specifically referred to enforcement of a subpoena by an order for arrest or a fine, and this implicitly excluded any other form of enforcement. The High Court had no difficulty rejecting this argument: Parliament had not intended to exclude an order for production, which is after all the point of the regime in the first place. The subpoena regime, consistent with the broader reforms of the TTPA, reflect a policy of mutual trust and confidence, so the rules contemplate that the safeguards against over-reaching subpoenas are supplied by the requirement to obtain leave of the trial court and for the respondent to apply to set it aside (which rights the respondents in this case had exhausted).

A fundamental policy of the TTPA is to leave consideration of the substance and merits of the underlying matters to one court, with the other court lending assistance subject only to ensuring basic safeguards are present. This may be seen in the rules for staying proceedings where the courts of the other country are more appropriate (eg Whyte v a2 Milk Company Ltd [2023] 2 NZLR 486 in the context of class actions), enforcement of judgments (eg Lange v Lange [2021] NZFLR 719), anti-suit injunctions (A-Ward Ltd v Raw Metal Corp Pty Ltd [2024] 2 NZLR 475) or interim relief in support of proceedings in the other court (Wikeley v Kea Investments Ltd [2024] QCA 201).

Thus, the Court in Sunnya rejected the respondents’ reliance on the principle that “a state should refrain from demanding obedience to its sovereign authorities by foreigners in respect of their conduct outside the jurisdiction” (MacKinnon v Donaldson Lufkin & Jenrette Securities Corp [1986] Ch 482); implicit in the High Court’s reasoning is that there could be no objection to the Australian court issuing an extraterritorial subpoena because it was the very purpose of the regime to authorise them being issued and enforced. At common law, it is doubtful whether an extraterritorial subpoena could be enforced (and therefore should be granted in the first place): Hurtigbat Vestfold Sverige Line AS v The Ship “Om” (2000) 16 PRNZ 469. In the absence of the statutory regime, the New Zealand court would inevitably not grant orders to enforce a subpoena issued by a foreign court, not least because from the perspective of New Zealand courts the foreign court would not have had subject-matter jurisdiction to grant it.

It is also noteworthy that the Court was prepared to enforce the subpoena notwithstanding the (quasi)-criminal context. The subpoena had been issued by the New South Wales Supreme Court in proceedings for contempt taken against the second respondent (and that Court rejected the proposition that the potential incrimination of the second respondent was a valid excuse for the first respondent to refuse to comply). And, of course, quasi-criminal consequences flow directly in New Zealand from a failure to comply with the Australian subpoena. Again, these considerations would have loomed large at common law, since it is a general principle that the New Zealand courts will not lend their assistance to the enforcement of foreign penal laws. It was a matter for the Australian court to consider whether the potential incrimination of the second respondent offered a basis to have the subpoena set aside; those arguments being exhausted in the Australian court, it was the duty of the New Zealand court to ensure the subpoena could be given effect.

Finally, the decision touches on interesting issues concerning contempt by third parties who are not parties to a court order but aid or abet its breach (including in their role as directors). That will be the subject of further commentary from Maria Hook in a subsequent post.