Kevin Rudd won't say whether Labor will respect Tony Abbott's mandate to scrap the carbon price if the coalition wins the election.
Mr Abbott on Monday reiterated his vow to scrap the carbon tax if he takes power on Saturday, and warned Labor not to stand in his way in the Senate.
The opposition leader has repeatedly said he would call a double dissolution election if Labor failed to respect the coalition's "mandate" to junk the tax and other Labor policies.
But asked what Labor might do if the polls are right and it's forced into opposition, the prime minister was coy.
"Post-election speculation is something I don't enter into," Mr Rudd told ABC radio on Tuesday.
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Mr Rudd said Mr Abbott was at best a climate change sceptic, and at worst a clime change denier.
He said Mr Abbott had walked away from Australia's international commitment, shared by both sides of politics, for a five per cent reduction in emissions.
"I don't believe that's an acceptable or responsible response," he said.
"Mr Abbott has said if his so-called direct plan doesn't work, then so be it, and he would therefore break his pledge and Australia's international commitments to reduce carbon pollution."
Climate Change Minister Mark Butler said Mr Abbott's mandate argument, that a losing party should just junk all its policies to respect the winning side's mandate, was a fallacy.
"We are simply not going to junk our longstanding policy position on the most effective way to deal with climate change no matter what happens on Saturday, whether we win, lose or draw," he told ABC radio.
Asked if that would that mean using numbers in the Senate to force a coalition government to go to a double dissolution in order to repeal Labor's emissions trading scheme, due to start in July 2014, he replied: "We'll see what happens."
Australian Greens leader Senator Christine Milne said the Greens would do everything they could in parliament to stand up to Mr Abbott's "anti-science" approach to climate change.
"We will never allow them (the coalition) to repeal a price on pollution, and we will stand firm on that," she told reporters in Sydney.
She added that the Greens would be needed in the Senate to keep Labor on track.
"When push comes to shove you can't trust Labor on the environment," she said.
"But if the Greens are there we will continue to argue the case and hopefully bring Labor with us to stand up against Tony Abbott."
Australia could become an international laughing stock if it ended up with a prime minster who believed global warming was a "philosophy", Senator Milne said.
