Cracks have emerged in federal Labor ranks with two party MPs conceding the incoming government's plan to scrap the carbon tax should be allowed to pass parliament.

Backbencher Nick Champion and Richard Marles, Labor's most recent trade minister, on Wednesday broke the party line which has promised to block moves in parliament to repeal the impost on emissions.

"We do need to acknowledge the fact that Tony Abbott won the election, and we lost," Victorian MP Mr Marles told Sky News.

The coalition classified Saturday's election as a referendum on climate change and say they come to power with a mandate to remove the tax.

"If the majority of people vote for bad policy, then they simply need to see that experiment fulfilled," Mr Champion told ABC radio.

"It's not our job to save the Liberal Party from bad policy and it's not our job to save the Australian people from bad policy if that's what they choose and vote for in an election."

Incoming climate action minister Greg Hunt welcomed the "good sense" of the Labor duo.

"There can be no reason and no excuse for the ALP not to honour a fundamental, central referendum question," Mr Hunt told reporters in Canberra.

But others in Labor remained steadfast in their opposition of the coalition's intention to shift to a direct action plan to combat climate change.

Sydney MP Michelle Rowland said the plan, which includes using soil and trees to soak up emissions, is an "absolute figleaf".

"I'm not voting for a policy about planting trees and magic soil," she said.

Mr Champion did not agree with the coalition policy and said it should be opposed in the lower house, but allowed to pass the Senate, to expose the shortcomings of the incoming government.

"In effect, I think the Liberal Party want to hang themselves," Mr Champion said.

"Well, we should give them as much rope as they need."

Asked if the coalition would push ahead with its threat of a double dissolution election to see its policy pass the parliament, Mr Hunt said "there is a long way to travel" before reaching that consideration.

When Labor came to power in 2007 Mr Hunt said the coalition accepted and honoured the new government's mandates including signing the Kyoto Protocol, shifting away from WorkChoices and the government apology to indigenous Australians.