Labor has accused the Federal Government of being deeply divided on climate change after senior minister Malcolm Turnbull likened the Government's renewable energy target (RET) to a carbon tax.

The Coalition has run a long campaign against Labor over its previous policy for a fixed price on carbon, calling it a carbon tax.

And the Labor plan to reinstate an emissions trading scheme (ETS) has led Prime Minister Tony Abbott to warn that the policy would install a floating "carbon tax".

Mr Abbott repeated the ETS criticism on Monday, calling the policy an "electricity tax scam".

But Mr Turnbull suggested the RET still carried a cost for households and could be considered a tax.

"Whether it's a regulation, whether it's a RET, ETS or carbon tax fixed price, all of those can be seen as a cost on the business of generating energy and therefore a cost on households purchasing energy, and therefore in that sense a tax," Mr Turnbull said.

Labor's environment spokesman, Mark Butler, issued a statement saying Mr Turnbull had called "bullshit on Tony Abbott's scare campaign".

"Prime ministerial aspirant Malcolm Turnbull has today slapped down Tony Abbott's climate change scare campaign in an extraordinary way," he said.

"Malcolm Turnbull today defied his leader to say that an emissions trading scheme is not a tax.

"Mr Turnbull lost the Liberal Party leadership for supporting an emissions trading scheme.

"Labor will increase Australia's renewable energy mix to 50 per cent with an emissions trading scheme to take action on climate change.

"Only Labor — and Malcolm Turnbull — take the need for strong action on climate change seriously."

On Monday, Mr Abbott attacked Labor's plans for a 50 per cent RET by 2030, warning it would allow a "massive overbuild of wind farms" and cost tens of billions of dollars.

Labor announced the proposal for the increased RET ahead of the party's national conference, doubling the existing 2020 target of 23.5 per cent.

"One of the truly bizarre decisions coming out of the Labor conference on the weekend was this move to increase the proportion of renewables in our system, to some 50 per cent," Mr Abbott said.

"This constitutes a massive hit on consumers and on jobs."

He said the cost of such a significant shift would be "massive ... perhaps $60 billion or more" and would lead to an oversupply of wind energy.

"You've got this massive and unnecessary commitment to renewables, which will cause a massive overbuild of wind farms, all of which has to be paid for by the consumers," Mr Abbott said.

But Opposition Leader Bill Shorten dismissed the criticism, saying the Prime Minister "just makes up numbers to scare people".

"He has no evidence or science, in fact he is the most unscientific prime minister Australia has had in a long time," Mr Shorten said.

Labor leaders talk to Gore about climate policy

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The Labor leader has been in talks with former United States vice president Al Gore, who has flown to Australia ahead of the international climate talks in Paris later this year.

"Vice President Gore congratulated Labor on taking a stand which will see the future for Australian brighter than it otherwise would be," Mr Shorten said.

Mr Gore also consulted with state Labor leaders on climate policy.

"This is the tipping point year for action on climate," the international environmental campaigner said.

"The meeting in Paris is shaping up as a success."

The Coalition still has not revealed the post-2020 target it will take to the Paris meeting, and Mr Abbott said he would consult with his party room when Parliament returned next month before a final number was chosen.

Mr Gore said there are many people around the world who think of Australia as a leader on climate policy.

"Some have been, frankly, scratching their heads of late wondering what has been going on," he said.