People who "hate" right-leaning opposition leader Peter Dutton had flocked to Labor to keep him out of power, Bandt told reporters after losing the seat of Melbourne, which he held for 15 years.

"Like me, many of them wanted him as far away from power as possible," Bandt said.

"My initial take is that some votes leapt away from us to Labor, as people saw Labor as the best option to stop Dutton," he said.

"Whilst not a massive shift in the vote, it did make a difference."

Bandt, 53, said he had called his Labor Party rival for the seat, Sarah Witty, to congratulate her and "wish her all the best".

Left-leaning Prime Minister Anthony Albanese's Labor Party won re-election in a landslide Saturday, with partial results putting it on course for at least 92 seats in the 150-member House of Representatives.

The Greens have secured no seats so far, though one is still considered too close to call.

They had four seats in the previous parliament.

But Bandt said the Greens may get 13 percent of the vote in the upper house Senate, giving them the balance of power there.

- 'Climate denialist' -

"Fighting the climate crisis is the reason that I got into politics, and I want to thank everyone in Melbourne for helping us make a difference," he said.

"If the government doesn't use its big majority to start actually cutting climate pollution and tackling Australia's massive inequality crisis, watch for a big swing at the next election."

Dutton, who was leader of the opposition Liberal-National coalition, lost his own seat as well as leading his party to crushing defeat in the general election.

He had touted a US$200-billion plan to introduce nuclear power to Australia by building seven large-scale nuclear plants by 2050 -- doing away with the need to ramp up renewables.

Albanese has poured public money into the renewables sector, which he says will supply 82 percent of Australia's electricity by 2030. But he has still approved fossil fuel projects.

"The government has been lucky to have a climate denialist, Peter Dutton, for many years as their foil, because it made them look good," Bandt said.

"As the political debate became about renewables versus nuclear, we tried really hard to get people to pay attention to coal and gas and the over 30 new coal and gas projects that have been adopted," he said.

"Please, please start taking the climate crisis seriously and holding this government and any future government to account."

Bandt, who is married with two daughters, became Greens leader in 2020.

He worked as an industrial lawyer representing workers against corporations, including defending the rights of coal workers in privatised power stations.