Like other countries that pride themselves on upholding the rule of law, New Zealand has seen many climate change cases decided by its courts. The most significant is the 2024 judgment of the Supreme Court in Smith v Fonterra. The country’s highest court unanimously allowed an appeal against the lower courts’ decisions to strike out a tort case brought by a well-known Māori environmental activist, Mike Smith (Ngāpuhi, Ngāti Kahu), against major corporate emitters of greenhouse gases (GHGs) in the agricultural, energy, and mining sectors. As a result, Mr Smith’s case can proceed to trial—scheduled for 15 weeks from April 2027—whereby he seeks declaratory and injunctive relief under two causes of action: public nuisance and a novel climate tort.
However, on 12 May 2026, the Minister of Justice announced the Government’s plan to “amend the Climate Change Response Act 2002 to prevent findings of liability for tort for climate change damage or harm caused by [GHGs] in both current and future proceedings before the courts.” This plan spurred immediate criticism from Mr Smith, prominent lawyers, opposition MPs, and NGOs. Academics have since weighed in here and there. Yet, because New Zealand’s constitution is based on the least restrictive model of parliamentary democracy, a bare majority of Government MPs could strip Mr Smith and other potential litigants of their rights at common law without any judicial review.
But the fact that an act of Parliament is taken to be supreme by domestic courts does not mean that act is internationally lawful. This post asks a simple question, informed by New Zealand’s Legislation Guidelines: would the Government’s amendment to bar climate tort litigation “be inconsistent with existing international obligations”? In answering this question, I address three relevant areas of international law: climate law, human rights, and New Zealand’s free trade agreements (FTAs).
In summary, the Government’s plan, together with its overall programme of legislative and executive action, may be inconsistent with at least three international obligations: (i) the duty to exercise due diligence in preventing significant harm to the climate system, specifically by regulating corporate emitters and, arguably, maintaining access to justice; (ii) Mr Smith’s right to a fair and public hearing of his civil claims, which is the clearest of possible human rights violations; and (iii) the obligation under certain FTAs not to weaken or reduce the levels of protection afforded in environmental law in order to encourage investment. These conclusions should be taken seriously by Parliament and may help others to identify pathways to challenge or otherwise respond to the Government’s plan to deny justice to Mr Smith.
Climate law
New Zealand’s climate obligations are sourced both in treaties, foremost the Paris Agreement, and in generally applicable rules of customary international law. In its 2025 advisory opinion, the International Court of Justice (ICJ) reaffirmed that each State has a stringent duty under treaty and custom to exercise due diligence in preventing significant harm to the climate system, entailing a duty to regulate the conduct of private actors that cause climate change through their GHG emissions, above all fossil fuel companies (paras 427–428).
The ICJ did not squarely address the issue of corporate climate accountability under domestic law, except to acknowledge that “strict liability of private actors for specific hazardous activities” may be imposed by “sector-specific treaties and various types of national legislation” in accordance with the “polluter pays” principle (para. 160). However, the ICJ endorsed a previous opinion of the International Tribunal for the Law of the Sea in holding that the duty of due diligence requires a State to “use all the means at its disposal” in establishing a “national system” to “regulate the conduct of public and private operators”, including “effective enforcement and monitoring mechanisms” (paras 281–282). In a similar vein, though not directly applicable to New Zealand, the Inter-American Court of Human Rights emphasised a State’s obligation to guarantee access to justice in the maintenance of “strong and independent mechanisms, whether administrative, quasi-judicial or judicial,” to supervise and monitor corporate conduct as part of its “enhanced due diligence … in the context of the climate emergency” (paras 233–236, 345–351, 540–551).
Read together, these three advisory opinions indicate the potential importance of maintaining—or, at least, not dismantling—the national justice system in respect of corporate emitters as a part of a State’s overarching duty of due diligence under international climate law. Indeed the declaratory and injunctive relief sought by Mr Smith from the High Court would itself perform a “regulatory function”, observes Bookman, by “requiring (or pressuring) the defendants to change their future course of conduct, and deterring other similarly-situated companies”, whilst “prodding legislators and executives to respond by revisiting their own (inadequate) regulatory schemes.” Any legislative or executive interference with access to environmental justice may therefore be attributed to New Zealand in determining whether it has diligently regulated corporate emitters to prevent significant climate harm (Articles on State Responsibility, arts 4, 15).
In assessing the overall adequacy of New Zealand’s conduct, the Government’s plan to bar claims in tort cannot be viewed in isolation from its apparent programme to water down the national system for responding to climate change and other types of environmental harm. The Crown Minerals Amendment Act 2025 reversed a 2018 ban on new oil and gas exploration. A raft of other legislation—the Fast-track Approvals Act 2024, the Planning Bill, the Natural Environment Bill, the Conservation Amendment Bill, and the Environment (Disestablishment of Ministry for the Environment) Amendment Bill—has been heavily criticised for reducing environmental protection and sidelining climate change, attracting almost 27,000 submissions on the Fast-track Approvals Act alone, around 90% of which were opposed. More recently, the Government rejected all of the Climate Change Commission’s recommendations to strengthen New Zealand’s 2050 GHG emissions reduction targets.
Against this backdrop, a statutory bar on climate tort litigation may form part of a series of acts and omissions that in aggregate are hard to reconcile with New Zealand’s duty to exercise due diligence by “taking the necessary regulatory and legislative measures to limit the quantity of emissions caused by private actors under its jurisdiction” (Climate Change Opinion, para. 428).
Human rights
The purpose of the bar, according to the Minister, is to defeat Mr Smith’s case: “Ongoing litigation in the High Court, where an applicant has brought civil claims against six major businesses for their [GHGs], is creating uncertainty in business confidence and investment that the Government must address.” However, as the Human Rights Committee (HRC) confirmed in General Comment No. 32, the right to “a fair and public hearing by a competent, independent and impartial tribunal established by law” under Article 14(1) of the International Covenant on Civil and Political Rights (ICCPR) encompasses “judicial procedures aimed at determining rights and obligations pertaining to the areas of contract, property and torts in the area of private law” (para 16). In KlimaSeniorinnen v Switzerland, the European Court of Human Rights held that the equivalent “right of access to a court” was violated where the Swiss courts dismissed climate claims without examining their merits or the scientific evidence (paras 629–640). Mr Smith’s right would be more fundamentally violated by Parliament legislating to extinguish his access to environmental justice.
We have been here before. In Mahuika v New Zealand, 19 Māori individuals alleged that New Zealand violated Article 14(1) of the ICCPR by enacting the Treaty of Waitangi (Fisheries Claims) Settlement Act 1992, which discontinued proceedings that were pending before the courts without the consent of their iwi (tribe) or hapū (sub-tribe). The HRC held there was no violation in these “specific circumstances” because “the discontinuance occurred within the framework of a nation wide settlement of exactly those claims that were pending before the courts and that had been adjourned awaiting the outcome of negotiations” (para. 9.10). However, the HRC reaffirmed that “in the abstract it would be objectionable and in violation of the right [of] access to court if a State party would by law discontinue cases that are pending before the court” (emphasis added). That situation is no longer abstract, but the concrete situation in which Mr Smith would find himself.
The violations may run deeper. As the Supreme Court observed, Mr Smith alleges that the defendants “have contributed materially to the climate crisis and have damaged, and will continue to damage, his whenua [land] and moana [sea], including places of customary, cultural, historical, nutritional and spiritual significance to him and his whanau [family]” (para. 3). Notably, in Billy v Australia, the HRC held that Australia violated Article 17 (right to private, family and home life) and Article 27 (right to minority culture) of the ICCPR by failing to take mitigation and adaptation measures to combat the negative effects of climate change on the Indigenous people of the Torres Strait Islands. In view of such cases, the Government’s interference with Mr Smith’s claims against corporate emitters, combined with its own lax climate action, may form part of a range of human rights violations, not just of his right to a fair and public hearing.
Trade agreements
We must focus on the Minister’s explanation: “Our government is committed to fixing the basics, and certainty of law is essential for businesses to operate, attracting overseas investment, and stimulating economic growth” (emphasis added). Indeed the Government’s political commitment to “unlocking development and investment” has been a driver of the many changes to environmental law, mentioned above. However, New Zealand has legally committed to non-regression clauses in several of its FTAs, such as Article 19.2.4 of the EU-NZ FTA: “A Party shall not weaken or reduce the levels of protection afforded in its environmental … law in order to encourage trade or investment.” Similar but somewhat looser obligations are found in Article 22.4.3 of the UK-NZ FTA, Article 16.2.6 of the Korea-NZ FTA, and Article 20.3.6 of the 12-party Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP). All of these obligations are subject to inter-State consultation or dispute resolution obligations.
There are several interpretive steps in determining whether a statutory bar on the right to sue in tort for climate harms would be inconsistent with non-regression obligations. Levels of environmental protection are typically understood as those set by regulatory agencies, not by the possibility of litigation. But the Climate Change Response Act plainly falls within the open-ended definition of “environmental law” under the UK-NZ FTA and CPTPP; the term is left undefined in the other FTAs. And it is clear from the Minister’s explanation that the Act’s amendment is intended to encourage investment. Without any compensating protection, a bar on climate tort litigation would likely weaken or reduce the level of environmental protection. Under the EU-NZ FTA, at least, there is no need to establish any causal link with the bar’s effect on investment, whereas the Korea-NZ FTA would likely require evidence that weakening or reducing environmental protection has actually affected bilateral trade or investment.
For New Zealand’s FTA partners, the bar may be viewed as one among many regressions from environmental protection. Foreign investors have indeed been encouraged by last year’s reversal of the 2018 ban on oil and gas exploration, evident in recent applications by Australian and Canadian companies for exploration permits. Any decision by the Minister for Resources under the Crown Minerals Act 1991 in respect of such permit applications would still need to consider climate change, according to a 2025 judgment of the Supreme Court. When asked whether the Government intended to amend the Act to reverse this judgment, the Minister quipped that “the highest court in the land is Parliament”. However, the Government would do well to recall that “the granting of fossil fuel exploration licences”, in the ICJ’s authoritative opinion, “may constitute an internationally wrongful act which is attributable to that State” (para. 427).
Regardless of any inconsistency with New Zealand’s FTA obligations, it is extraordinary for a State to immunise future polluters from tort liability in order to encourage investment. Arbitral tribunals in investor-State dispute settlement (ISDS)—which are often assumed to have a singular focus on investment protection—have acknowledged that “judicial bodies across the globe are widely recognized to validly lead the way in the development of the law according to society’s evolving values” and have been particularly “mindful of the role of the judiciary in common law jurisdictions”. Some tribunals have allowed States to bring counterclaims in contract or tort for environmental damage caused by investors, including for alleged climate harms caused by GHG emissions. All to say, the Government’s plan is out of step even with international investment law.
Justice denied
Let us end by comparing Mr Smith’s vulnerable position to that of another litigant with an unassuming name: Robert Brown, a US mining engineer in the Transvaal who is likewise associated with a constitutional controversy. In 1895, Mr Brown secured a favourable judgment from the High Court of the South African Republic, which recognised the validity of his gold-prospecting licences and invited him to sue for damages if he was prevented from exploiting them. The legislature reacted by proclaiming the invalidity of his licences and that no damages could be awarded. Such legislation, in the 1923 decision of an international tribunal, did “violence to fundamental principles of justice recognized in every enlightened community” and, with “the obvious intent to defeat Brown’s claims, a definite denial of justice took place.”
Denial of justice is one of the oldest causes of action in international law and still finds currency in ISDS where, for example, a State passed retroactive legislation that extinguished a contractual right to commercial arbitration. Strictly speaking, a denial of justice arises whenever a foreign national suffers a fundamentally unfair judicial procedure; any legislative or executive interference with that procedure would rather breach the minimum standard of treatment. But these doctrines are closely allied in New Zealand’s investment treaty practice (CPTPP, art. 9.6.2(a)). Whereas the Government’s interference with any litigation or arbitration commenced by a protected investor may result in a substantial award of damages (CPTPP, art. 9.29), Mr Smith is left without obvious legal redress in advancing his climate claims, except to file an HRC communication.
This double standard is nothing new in the history of international law, nor that of Aotearoa. In 2004, Parliament stripped Māori of property rights in the foreshore and seabed as a populist reaction to the Court of Appeal’s affirmation of those rights, leading to criticism of New Zealand by the Committee on the Elimination of Racial Discrimination. One of the judges in that landmark case, Sir Kenneth Keith, sadly died the day after the Government announced its plan to bar climate tort litigation. Perhaps his legacy can encourage a new generation to strengthen the rule of international law in New Zealand and thus prevent denials of environmental justice to the likes of Mike Smith.
