A climate change revolt in Australia's governing coalition on Monday brought in a new deputy prime minister likely to challenge the country's already hesitant moves to cut greenhouse gas emissions.

Barnaby Joyce, best known internationally for threatening to euthanise Johnny Depp's dogs, defeated incumbent Michael McCormack in a snap internal party vote, elevating him to the role of deputy PM. 

The vote for the leadership of junior coalition partner the Nationals came as apparent cracks emerged in the ruling coalition over climate change policy. 

Prime Minister Scott Morrison told G7 leaders last week that Australia wants to achieve net-zero carbon emissions "as soon as possible", and preferably by 2050.

McCormack had reportedly been accused by party colleagues of failing to push back against such accelerated climate action, a charged topic among the Nationals' rural conservative voters.

On Monday, Joyce dodged questions on whether he would support Australia taking a net-zero by 2050 target to November's UN Climate Change Summit in Glasgow.

But he echoed conservative talking points that strong climate change action posed a threat to Australia's commodity-dependent economy.

"If the National Party room believes that the best deal for regional Australia is to make sure that we secure their jobs, is to make sure that we secure their industries... that's the view that I'll support," he told reporters in Canberra.

Joyce previously held the Nationals' leadership but stepped down in a 2018 scandal when it was revealed the married father-of-four had an affair with a young adviser and she was pregnant.

He was also accused of sexual harassment by a prominent rural woman but an internal investigation failed to reach a conclusive verdict.

Joyce called the allegations "spurious and defamatory", adding that after three years on the backbench he hoped to "be a better person to do a better job".

He gained international notoriety after threatening to put down Hollywood star Johnny Depp's two Yorkshire Terriers over a quarantine violation in 2015.

Morrison congratulated Joyce on his elevated role, saying in a statement that they shared a "passion for ensuring our regions and rural communities thrive".