Prominent human rights lawyer Julian Burnside QC says concern that the political system is "broken" has prompted him to run as a Greens candidate against Treasurer Josh Frydenberg at the next federal election.

Key points: The commercial litigation barrister is best known for his refugee advocacy

The commercial litigation barrister is best known for his refugee advocacy The affluent Kooyong electorate has been a safe Liberal seat since its creation

The affluent Kooyong electorate has been a safe Liberal seat since its creation Mr Burnside said the Greens had "matured" from an environmental protest party

He is the second high-profile candidate to challenge Mr Frydenberg in his Kooyong electorate in Melbourne's inner-east, after former Liberal Party member Oliver Yates threw his hat in the ring last year.

Mr Burnside said his wife had urged him to run for office, and he had decided to join the Greens about a week ago after he checked their policies and found they were "consistent" with his views.

The Melbourne barrister specialises in commercial litigation, but is best known for his advocacy for asylum seekers and has been a vocal critic of Australia's offshore processing centres.

"The Greens used to be regarded just as a party of environmentalists, I remember them when they set up in the early '90s, but they've matured," he told ABC Radio Melbourne.

He said while refugee rights was the major issue for which he was known, he believed climate change was "the major issue" facing the planet.

Josh Frydenberg has represented the electorate of Kooyong since 2010. ( ABC News: Andrew O'Connor )

"I've lived in Kooyong all my life, I think I understand Kooyong fairly well, and a lot of people in Kooyong are anxious to leave lots of wealth for their families for their kids, and their grandkids," he said.

"Well what about leaving a world that's able to support human existence? I think that's even more important.

"Politics is broken in this country. The major parties are both, I think, ineffective."

'Worth giving it a good belt'

Kooyong has always been held by the Liberal Party and its antecedents since the seat's creation in 1901.

Mr Burnside said he believed by attracting disaffected Liberal voters, he and Mr Yates could reduce Mr Frydenberg's primary vote enough to be in with a chance of a win.

"I think it's worth giving it a good belt," he said.

When asked what his view was of the internal disputes that marred the Greens' recent Victorian election campaign, Mr Burnside said he was "not interested".

Greens leader Richard Di Natale praised Julian Burnside's "passionate advocacy" for asylum seekers. ( ABC News )

"A few people are annoyed about the way things have happened in the party, well, that's a pity," he said.

"But it is still the fact that our political system in my opinion is broken and the Greens seem to be the only party who have got grown-up attitudes to the real problems facing the world."

Greens leader Richard Di Natale attended a launch for Mr Burnside's candidacy, where he said the barrister's stance on climate change and refugee rights aligned with the party's values.

"In Julian Burnside we're going to have a fierce advocate for those Greens values," Senator Di Natale said.

In a statement, Mr Frydenberg said "no seats are safe across Australia".

"I certainly do not take anything for granted locally and continue to work hard to deliver for my local community," he said.

Mr Yates said in a statement that the candidacy of Mr Burnside demonstrated the Liberal Party's hold on Kooyong was "clearly under challenge".

"It highlights how out of touch the Liberal Party has drifted, that two passionate people see the need to stand for election on their key issues, of climate and people seeking asylum," he said.