The New Zealand Greens will consider severing ties with Jacinda Ardern's Labour government in any ballot for the party's co-leadership role next month.
In an escalation of tension at the party's grassroots, would-be leadership aspirant Teanau Tuiono said abandoning ministerial roles and policy deals with Labour was on the table.
Mr Tuiono held a press conference on Wednesday to announce a possible tilt at the co-leadership position made vacant at the party's AGM last week.
At the meeting, co-leader James Shaw, also the climate change minister, failed to clear a 75 per cent satisfaction threshold among members.
Mr Shaw has been leader since 2015, but is considered too moderate by a section of the party membership.
Mr Tuiono said he "really liked" Mr Shaw and had been open with him about a potential challenge.
The party's first Pasifika MP said the co-operation agreement with Labour was "definitely something that's come up" among members.
"If that's not resonating outside, well then we should have a look at it," he said.
An end to the co-operation agreement would not affect Labour's ability to pass legislation, given their majority in parliament.
However, the move would be a blow for the prime minister's hopes of campaigning on stability at the 2023 election, or building a coalition with the Greens after it, should her party be returned to office.
Coalitions are common under New Zealand's electoral system, with Ms Ardern becoming prime minister in 2017 only with the support of the Greens and New Zealand First.
Ms Ardern said walking away would be "a significant departure" from the Greens.
"I would have an expectation that there would be no change to that agreement because there is no provision for change to that agreement," she said.
Greens co-leader Marama Davison, who survived a vote of her own at the AGM, confirmed her party's delegates had the power to decide.
"It will be up to the members to assess whether they think we are making enough gains, whether they think we are standing strongly enough on our Greens kaupapa values," she said.
Mr Shaw declined media requests for comment on Wednesday but wrote a lengthy Facebook post admitting he had neglected grassroots members.
"I need to show that commitment and passion for urgent radical change more clearly," he said.
"I hear your dissatisfaction with me and I want to take time to understand it.
"I guess I've thought that the best work I could do for the Greens was my work as climate minister.
"I can see that I need to spend more time working on my role as co-leader. If members do choose to have me back, I will do that."
