Peters rules out NZ Labour, lashes Ardern

Winston Peters has severed ties with Jacinda Ardern's government, promising to never again support or form a coalition with Labour while she is in charge.

The enduring force of New Zealand politics is attempting to once again enter parliament at the age of 78, after losing office in the 2020 Labour landslide.

It was Mr Peters' New Zealand First party which propelled Labour into power in 2017, making Ms Ardern prime minister after weeks of tense coalition negotiations.

In return, Ms Ardern made Mr Peters her deputy and foreign minister, posts he held for three years while Labour and NZ First governed together, with the Greens also taking posts outside cabinet in a tripartite coalition.

That working relationship is now dead, with Mr Peters saying the Ardern government's "dishonesty" meant he would not countenance supporting them after the 2023 election.

"Lying to their coalition partner and going back on their word is the reason we will not go back into government with them ... nobody lies to me and gets a second chance," he said.

Mr Peters accuses Ms Ardern's government of a separatist agenda as it commissioned a report into New Zealand's obligations under the UN Declaration on the Rights of Indigenous Peoples in 2019.

This has bled into an argument over "co-governance", a local byword for the growing Maori influence within government policy and decision-making.

The debate, which stems from alternate understandings of New Zealand's founding document - the Treaty of Waitangi - has an unfortunate racial tinge, and is something of an obsession of populist candidates like Mr Peters.

Mr Peters said Labour has a "separatist plan where some New Zealanders will have more rights than others".

Ms Ardern brushed off Mr Peters' attack, saying "lots of politicians say lots of things about one another".

"I'm going to maintain the ground I've stated on our coalition with New Zealand First. I was proud of what we did. I'm not rewriting history," she said.

Mr Peters' move recasts the 2023 election.

The move is bad news for Labour, who have lost a potential coalition partner as it seeks a third term.

It is the first time since forming NZ First in 1993 he has ruled out working with a major party prior to the election, which denies his party the potential kingmaker role after the poll.

It also effectively aligns NZ First with the opposition centre-right National party, which has overtaken Labour in most polls.

It's not certain NZ First will return to parliament, which requires five per cent of the national vote.

NZ First returned just 2.6 per cent in 2020 and is currently polling below that threshold, though support is growing.

Privately, Labour is casting the move in a positive light, given Mr Peters' populist policies are deeply unpopular with their progressive base.

Labour believe it heaps pressure on the National party to outline who their likely coalition parties are going to be.

In the words of one senior Labour figure, "he's National's problem now".

Opposition leader Chris Luxon is yet to publicly canvass possible governing partners, saying it was "way too early" to do so.

National has ruled out working with Mr Peters under two previous leaders, including John Key - Mr Luxon's mentor.