The Rudd government has questioned whether there's any point to negotiating on emissions trading when the coalition remains unmoved on the science behind man-made global warming.
Labor has also taken another crack at Malcolm Turnbull and his shaky grasp on the leadership, this time blaming him for thwarting good faith negotiations by having failed to earn the backing of his party room.
Negotiations plunged to a new low on Monday after Opposition Senate Leader Nick Minchin declared most of the coalition did not believe humans had contributed to climate change.
It prompted the government to question the validity of last-minute negotiations on its carbon pollution reduction scheme, set to go before parliament next week.
Deputy Prime Minister Julia Gillard asked how discussions could be fruitful if Mr Turnbull had failed to win over party room mates on the veracity on climate change.
"We saw senior coalition figures basically trash Mr Turnbull's agenda, (so) we're entitled to ask a question ..." Ms Gillard said on Tuesday.
"That question is, is Malcolm Turnbull in a position to say that in negotiating in good faith, that he's got his party's support?
"Because if he isn't, then what are we negotiating about?"
Attempting to tighten the noose, Ms Gillard said the embattled opposition leader must come good on his earlier promise to negotiate a climate change deal, or else leave.
"We need Malcolm Turnbull to do no more or no less than he said he would - he said he didn't want to lead a party that wasn't with him on climate change.
"All we're asking him to do is honour his words.
"He's got to get his party to follow him."
Climate Change Minister Penny Wong and the opposition's negotiator, Ian Macfarlane, met again on Tuesday to discuss amendments to the government's scheme.
Negotiations had been made that much worse after Senator Minchin's comments, Senator Wong told ABC Radio.
"I think it will be particularly difficult given what happened last night on the television," she said.
"There are too many people in the Liberal Party who are not fair dinkum on climate change, who do think it is some sort of conspiracy."
Even if a deal was brokered, it would be tough for Mr Macfarlane to get the agreed amendments through the party room, said Senator Wong, who called on Mr Turnbull to repudiate his wayward colleagues.
Some senior coalition figures heaped coal on the fire by claiming Mr Turnbull was "too green" for the rest of the party, and a Nationals senator's claim that the emissions trading scheme - amended or not - would not get past the Senate.
On Tuesday, the comments didn't stop - with Liberal backbencher Bronwyn Bishop announcing Senator Minchin had got it right on the number of climate change sceptics within the party.
But Mr Turnbull would not waver from his traditional line on Tuesday, saying he remained focused on the negotiations, refusing to comment on his wayward colleague's comments.
He reaffirmed his belief that global warming was because of human activity.
Deputy opposition leader Julie Bishop later rejected Senator Minchin's comments that the majority of the coalition gave no credence to man-made climate change.
"That might be Nick's personal view, and he's entitled to have a personal view. It's not my view," she told Sky News.
"My understanding is that the party room gave Ian Macfarlane authority to negotiate a range of amendments in good faith with the government."
Senator Minchin's comments had been pre-recorded "some weeks ago" and events had since moved on, she said.
The negotiations would not be derailed.
"We had a process in place, we are still proceeding to negotiate the matter, we'll then come back to the party room and then we'll vote on it in the parliament."
Front page
RSS Feed