The Liberal Party's most recognisable climate campaigner has been tapped by Labor to assume Australia's top climate advisory role.

Prime Minister Anthony Albanese announced on Monday morning that former NSW treasurer and energy minister Matt Kean would head the Climate Change Authority, just days after his surprise exit from state politics.

There had long been speculation that Mr Kean, a leading moderate and a popular minister in the Berejiklian and Perrottet governments, would head to Canberra, but few expected him to do so as a bureaucrat rather than an MP.

The timing of the announcement, just days after federal Liberal leader Peter Dutton unveiled his long-teased nuclear power policy, is unlikely to be a coincidence.

Mr Kean has been a vocal nuclear critic, a theme he returned to in a press conference on Monday morning.

"We looked at all options including nuclear," Mr Kean said, reflecting on his time in the NSW government.

"And the advice I received … [was] it would take far too long and would be far too expensive for NSW. I didn't want to bankrupt the state and I didn't want to put those huge costs onto families.

"That is why we produced [a plan for] the transition to renewables, backed by firming and storage, because we know that is the cheapest option for NSW."

Just weeks ago, he was even stronger, calling the idea a "Trojan horse" for the coal industry in his state.

Though he had previously avoided weighing in on the national debate, it will now be his job to do so.

The authority was established in 2011 to provide expert advice to the government on climate policy.

But since Labor's election in 2022, its role has been expanded. It prepares an annual independent statement on climate progress to parliament and it also provides independent advice on targets for emissions reduction.

That means the first two tasks for Mr Kean will be tracking whether the government achieves its 2030 target and advising on what its 2035 target should be.

That latter target is due to be finalised next year, but Prime Minister Anthony Albanese has recently been reluctant to talk about it and repeated on Monday his main focus was on 2030.

Mr Kean will need to provide advice on the 2035 target in October, working alongside Chief Scientist Dr Cathy Foley and the authority's six other members, a group that until recently included incoming governor-general Samantha Mostyn.