Iwi leader and climate activist Mike Smith is accusing the government of a "co-ordinated campaign of secret lobbying, political interference and corporate influence at the highest levels of power".
He says the government's changes to climate law to prevent lawsuits has "exposed" what appears to be a "deliberate effort" to conceal communications between the Prime Minister's office and the companies Smith is taking to court.
A spokesperson for the Prime Minister says his office was made aware of these meetings and briefing notes through the media, "and have no record of either on file".
Official documents released Sunday, and seen by RNZ, reveal a briefing document provided to the Prime Minister's office regarding Smith's case against Fonterra and other major emitters.
Z Energy confirmed to RNZ it had provided a document to government in 2024 and Fonterra confirmed it had done the same with a hard copy.
Smith explained the defendants in his case had been ordered to release documents relating to their lobbying efforts by the end of March 2026, but the briefing note was only released this month, through the discovery process in the High Court.
The documents also showed the information was not disclosed by the Prime Minister's office, when requested as part of a separate Official Information Act request by an environmental group
A spokesperson for the Prime Minister told RNZ there was no record of the briefing note on file and stakeholders on all sides of issues requested to meet with staff, but Cabinet "makes its own decisions".
The spokesperson said Cabinet made a decision on this issue to ensure businesses had legal clarity and certainty.
Speaking to Morning Report on Monday morning, Prime Minister Christopher Luxon reiterated his office had no record or recollection of the document.
"Our office have looked into the issue and they've just got no record, no recollection of this from 2024. Obviously there's a dispute there between the two, between the OIA and what Fonterra or Z are saying and ideally, maybe it should've been captured but our office has no record or recollection of that."
Luxon said climate change frameworks are put in place by governments and administered by the state - not by courts.
"What you don't want - and none of us wanted - would be a precedent where there's duplicating or a parallel system establishing massive amounts of uncertainty for businesses in New Zealand..."
This month, the government announced it would amend climate laws to prevent companies from being sued over damage caused by greenhouse gas emissions.
Justice Minister Paul Goldsmith said it would apply to current and future cases, stopping a landmark case against Fonterra and five other major emitters in its tracks.
Goldsmith said the law change would "remove the possible development of a new regime that contradicts the framework Parliament has already enacted to respond to climate change".
Documents released by the High Court revealed that, in mid-2024, a member of Fonterra's government affairs team printed out a "briefing note" and provided it to a staff member of the Prime Minister's office.
As well, in mid-2024, a member of Z Energy's government affairs team printed a copy of the same or similar document, and also provided it by hand to a staff member of the Prime Minister's office.
The briefing note explained the "rationale for proceeding with the introduction of legislation to prevent private litigation seeking to impose liability for climate change, including current litigation brought by Mr Michael John Smith against Fonterra, Genesis, Z Energy, New Zealand Steel, Dairy Holdings and BT Mining".
The briefing note, "in summary", explained why legislative intervention "is necessary and appropriate", and it proposed a two-sentence legislative amendment to the Climate Change Response Act 2002 that would "resolve the uncertainty and risks posed by private law claims like Mr Smith's".
The information was released after Goldsmith's announcement of the government's intentions on 12 May.
Smith explained the defendants in his case had been ordered to release documents relating to their lobbying efforts by the end of March 2026, but he only learned of the briefing note, after they were disclosed to him by Fonterra and Z Energy, following Goldsmith's announcement.
"These documents were supposed to have been discovered by the defendants, but it seems they were kept from me, while decisions were being made behind closed doors," said Smith.
Z Energy told RNZ it stood by the document, which summarised its views on the implications of the case. It said it was appropriate to engage with government on industry issues that had "economic and environmental issues of national significance".
It supported the government's decision to progress legislation "re-inforcing the Climate Change Response Act as the primary mechanism for addressing climate change".
Fonterra told RNZ it routinely shared information with stakeholders in various forms, including hard copy, "as was the case in this instance".
Furthermore, the Environmental Law Initiative (ELI) said it had sought information in March 2025 about meetings, discussions or conversations regarding the Smith case, and any proposed legislative or regulatory response.
Dr Matt Hall, the group's research and legal director, said it received "only limited material" in response.
"To see this document emerge later in such an important case is deeply troubling," said Hall.
ELI said it appeared the Prime Minister's office withheld a document that now showed direct lobbying of PMO staff by the defendants in the Smith case. The document only came to light due to "discovery obligations" on the various corporate defendants, the group said.
Smith said it increasingly looked like a "cover-up of secret lobbying" between the government and some of the country's most powerful corporate interests.
"This is not just about climate change anymore," he said. "This is about whether billion-dollar corporations can use their political access to shut down legal challenges they do not want to answer."
ELI has called for an Ombudsman inquiry and a Solicitor-General review, due to the document not being disclosed as part of its official information request.
