Australia's conservatives elected hardliner and China hawk Peter Dutton as the country's new opposition leader Monday, an outcome many will see as a lurch to the right for his party.

Dutton came out swinging after accepting the top spot, saying the country's newly elected Labor government was not "ready to govern and we are already seeing their inexperience on display".

Elected unopposed, the former police officer inherits a Liberal party decimated by Australia's May 21 election, when many of its long-time voters swung to independent candidates who promised action on climate change.

The new opposition leader will have to rebuild his shattered party and try to unite its fiercely divided moderate and conservative wings, with climate a key sticking point.

Dutton described himself Monday as "a very passionate believer" in Australia's need for an "appropriate response" to emissions reduction.

During his two decades in politics, the Queenslander has made a name for himself with tough talk and a penchant for headline-grabbing commentary.

On election day, he tweeted out a Border Force statement about the interception of an asylum seeker boat, adding his comment: "Don't risk Australia's national security with Labor."

In previous posts as defence minister, Dutton often likened China's expansionist ambitions to Nazi Germany.

"The only way you can preserve peace is to prepare for war," he said in one.

During Monday's speech, he described China under Xi Jinping as "the biggest issue our country will face in our lifetime".

Australia's opposition has elected Peter Dutton -- a former police office and defense minister -- as its new leader
Australia's opposition has elected Peter Dutton -- a former police office and defense minister -- as its new leader POOL via AFP / LUKAS COCH

Dutton served as Australia's immigration minister for nearly four years, overseeing the country's widely criticised offshore detention regime.

He sparked outrage when he claimed some asylum seekers who said they had been raped in Australia's offshore detention centres were "trying it on" by seeking an abortion on the mainland.

He also had to apologise after a quip about the threat climate change poses to the Pacific was picked up by a microphone.

"Time doesn't mean anything when you're about to be, you know, have water lapping at your door," Dutton was caught saying.

Dutton and his allies in the Liberal party have sought to play down his right-wing past since the election, saying Australians will see his softer side.

The new opposition leader said Monday his policies would be "squarely aimed at the forgotten Australians, in the suburbs, across regional Australia".

He also expressed regret about a decision earlier in his political career to boycott a national apology to Aboriginal Australians forcibly separated from their families.

At the time he believed "the apology should be given when the problems were resolved, and the problems are not resolved", Dutton said, citing the welfare issues many Indigenous Australians face.

Ousted Prime Minister Scott Morrison, who stepped down from the Liberal leadership after the election drubbing, offered his "full support" to Dutton on Monday.

Australia's newly elected Prime Minister Anthony Albanese last week praised Dutton, saying he had a better relationship with him than Morrison.

"Peter Dutton has never broken a confidence that I've had with him," Albanese said.