James Shaw has confirmed he will contest the Green Party's co-leadership after being ousted from the role.

"I am in it to win it," Shaw told reporters saying he had spoken to party members and family and had decided to stand again as Green Party co-leader.

Shaw made the announcement after failing to get the 75 per cent votes of delegates at the party's online annual meeting at the weekend to be reconfirmed in the role. Co-leader Marama Davidson was reconfirmed by delegates.

This opens up the co-leadership role this week to challengers.

Shaw said events of the weekend showed how much members cared, and if successful he would "redouble efforts" over the environment and poverty.

It was clear there was a lot more work to do, he said.

Polling for the Greens was up and higher than any point than when Jacinda Ardern took over as Labour Party leader.

Shaw said however he remained frustrated they had not gone as fast as they should.

Government could be "glacially slow" and did not match the speed of the climate crisis, he conceded.

Over coming weeks and months Shaw said he would listen to members up and down the country.

He had not heard from each branch but members nationwide who said they supported him.

After 2023 he saw the Greens again forming a government with Labour and said he would be co-leader.

He said did not want to betray confidence of caucus members around discussions with them if they would stand.

Asked if he would see a challenge as a betrayal, he said: "Have you met us?".

On Chloe Swarbrick specifically, Shaw said those conversations were between them and not for him to share.

On his climate change portfolio, Shaw said he was as frustrated as anybody at how long it had taken to get action on climate crisis.

He said he would continue pushing Government to go harder and faster.

"I'm in it to win it," Shaw said of upcoming co-leadership vote.

On strong support from co-leader Marama Davidson, Shaw said they had worked closely for years now and there was great admiration and trust.

Asked if he was out of touch with grassroots members, Shaw said he had support up and down the country but there had clearly been "some shift".

On the fact such leadership battles go on each year in the Green Party and potentially again in an election year in 2023, Shaw said it was a function of the Green Party as per the constitution.

"What I do hope is that this settles it."

Shaw said people had to remember the Green Party was founded by activists who had been fighting their lives for stronger action on climate change. There was a sense of urgency on climate change some felt was not matched by the Government, a sentiment Shaw said he shared.

"I actually share a lot of the frustration, even if that frustration is directed at me."

Asked if he was voted out Shaw said it was not something he was contemplating right now and would "cross that bridge" when it came to it.

He was "quietly confident" on the vote, he said.

Asked if his broad spectrum work on climate change including working closely with farmers might have annoyed some of those in the Greens, Shaw said he was proud of that work but acknowledged, "It does come at some cost".

If he lost the co-leadership Shaw said he would continue as Climate Change Minister. His work there was "only just starting to bear fruit", he said.

'I'm not done'

"I'm not done," Shaw told RNZ earlier today.

After the vote Shaw had said he was "inclined" to stand again but would first seek feedback from his caucus colleagues and the wider membership. Prime Minister Jacinda Ardern confirmed he would retain his position as Climate Change Minister regardless of the leadership decision, he said.

The vote means any Green Party member can now put their name forward for the role over the next week before another vote within five weeks.

Prime Minister Jacinda Ardern said Shaw would continue as Climate Change Minister.

"It doesn't change anything for us as a Government and in fact his ministerial portfolios," Ardern told AM today.

"I have no intention of changing Minister Shaw from the portfolios he has, regardless of what the end point of the Green Party's leadership decisions are."

Ardern said she was made aware of the party's decisions after their annual conference.

She indicated that she was not aware that Shaw had confirmed that he would re-run for the role and said she'd most likely find out alongside everyone else.

If a new co-leader was appointed, she said a ministerial position would not be created for them.

"At any given point parties may change their leaders. For me particularly it was important about ensuring continuity – my view is that we wouldn't attach ministerial roles to co-leadership and in the last Government we didn't do that either," said Ardern.

She said Shaw worked exceptionally well in his ministerial role, worked really hard and was making significant progress to build consensus.

"For policies like climate change we really need that. We need to ensure that these policies don't change with governments or don't change we individuals, they need to endure."

Former Green Party communications director David Cormack said the party needed to settle on a co-leader swiftly as infighting does not look good heading towards next year's election.

Political scientist Lara Greaves said although the majority of delegates backed Shaw, Auckland Central MP Chloe Swarbrick's popularity could bring a needed change for the Greens, if she decided to seek the co-leader job. Swarbrick has not said whether she will put her name forward.

- Additional reporting: RNZ