Former Green Party leader James Shaw hasn't rejected the idea of taking the chairman role at the Climate Change Commission but is wary of the notion of a former politician working an apolitical job.

Shaw announced yesterday he would be stepping back as party co-leader - but will stay on in Parliament for the first reading of his Right to a Sustainable Environment Bill. Later that day, BusinessDesk managing editor Pattrick Smellie suspected Shaw could eventually replace Rod Carr as Climate Change Commission chair.

The veteran politician spoke to The Mike Hosking Breakfast this morning to discuss his resignation, during which Hosking brought up the role - suggesting the role was practically his to take.

"Well look, nobody has made any offers there and I don't want to speculate on rumours," said Shaw.

"I'm not entirely sure we should have former politicians in that role, but the whole idea was for [a politically independent] and expert-based and so on, and for a former politician to fill that role - if it was me or someone else, then they would have to demonstrate they have the full confidence of the house and the Government of the day."

Hosking suggested the role would embody what Shaw had achieved as Greens leader, showing an ability to work with both sides of the house, that those environments were important and politics of the day weren't so much.

Shaw agreed that his goal had been to always keep friends on both sides of the fence.

"Absolutely, that has been my guiding principle in my work - and at the same time I am a politician," he told Hosking.

"I've been the leader of a political party for coming up on nine years now, and so again, I think any of those sorts of roles that are supposed to be a-political, you sort of want to be making sure people completely trust you."

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Shaw was again encouraged by Hosking, pointing out he was good at advocating for the environment.

"Oh, well nice of you to say so, thank you very much, Mike. I'll put you on my reference list," the resigned party leader responded.

Current sitting chairman, Rod Carr's term is due to expire on December 8 this year, all nominations for board members - including the chair - must be considered and then recommended by the commission's Nominating Committee.

The decision is made by the Minister of Climate Change, Simon Watts - who would consult with all political parties in Parliament on their preferred candidate before an appointment is made.

When approached by ZB Plus on whether Shaw would be considered for the role, Watts said it would be inappropriate to comment before any appointment, or reappointment process was completed.

According to a commission spokesperson, board members are chosen to provide a mix of expertise to tackle the many challenges of climate change and to serve a term of up to five years.

Asked if his leadership partner, Marama Davidson would be staying on in her role, Shaw said his understanding was she wanted to lead the Greens into the 2026 election.

He said Davidson "was equivocal yesterday" due to her knowing that if she ruled anything out or guaranteed something would happen, then the situation changed, she would be pulled up on her answers.

"If you say one thing then and then something else happens in the future then someone will come and have a go at you for it. But she has said that she's committed to continuing the party into the future," he said.

Shaw was also pushed on why he chose to resign so soon after being recently elected into his role, he said he'd campaigned to be returned to Government for a third term.

Back in 2015, Shaw said, he'd claimed during his first stand as leader that he saw his role to take the Greens into Government for the first time and guide them safely through the other side.

"I feel as though I've done that now."

Shaw rubbished any suggestion he would be starting any political party of his own - one that would be "truly Green", as one Newstalk ZB texter put it.

"My time in politics is done," he said.

"I've been a parliamentarian for a decade now and it's time for me to do other things with my time."

Finally, Shaw was asked whether he believed the game was worth the blood - or if working in parliament was worth all the trials he'd faced over the years. He said his job had been the most rewarding, yet the most challenging he'd ever had.

He said it was an "incredible privilege" to work as the Climate Change Minister for six years, but it also provided "mind-bogglingly frustrating" moments during almost every day of his time in service.

"But I wouldn't have not done it would I be given the opportunity to do it again," he said.