The plan was alive for less than half a day before Climate Change Minister Penny Wong dismissed it as a shopping list of "vague and inconsistent demands".

Senator Wong said the Government would listen to Mr Turnbull only if he had a coherent set of instructions from the joint Coalition party room.

Prime Minister Kevin Rudd similarly gave it the thumbs-down, taunting Mr Turnbull to unify the warring Coalition before putting anything before the Government again.

Mr Turnbull is desperately trying to avoid giving the Government a double-dissolution trigger, which it would have if the Coalition voted against the emissions trading scheme bill.

But Nationals MPs, mollified on Friday by Mr Turnbull's proposal to quarantine agriculture from the pollution scheme, were again declaring war on the legislation yesterday.

Senator John "Wacca" Williams said he would rather walk away from Canberra with a clear conscience than vote for the legislation in its present form. "Permits could cost the agricultural sector $7 billion. Under that scenario there'd be no farmers and no food."

Senator Williams said the Government was only interested in getting a double dissolution trigger for an early election.

"Politics is what's behind it all, and we shouldn't be playing politics with Australia's future," he said.

The Nationals Senate leader Barnaby Joyce reiterated that he would not support the scheme, and other senior Nationals said they would never vote "for anything that looks remotely like the existing bill".

The Senate is due to vote on the bill on August 13.

If the Coalition opposes it, the Government could have a double dissolution trigger three months later, in November, if it reintroduced it and it was rejected again.