Opposition Leader Tony Abbott's push for an $80 million non-binding plebiscite on the proposed carbon tax is dead in the water after key Senator Steve Fielding rejected the proposal as a "political stunt".

Mr Abbott proposed the poll yesterday, but said he would still oppose a carbon tax even if voters gave it the thumbs up.

Calling the plebiscite a "glorified opinion poll", Senator Fielding said: "What we've got here is a political stunt which will waste taxpayers' money and achieve nothing."

The motion for a plebiscite is due to be introduced into the Senate today, but the Opposition needed the support of both crossbench senators, Nick Xenophon and Steve Fielding.

Senator Xenophon has been meeting Mr Abbott to have the wording of the motion changed from the "simplistic" for-or-against carbon tax to one that refers to action on climate change.

But Senator Fielding's decision means the motion will fail.

"It's an $80 million political stunt that even Tony Abbott has said is not binding," Senator Fielding said.

"Last week the Coalition argued that the Government shouldn't be allowed to spend taxpayers' money on spruiking a carbon tax because it didn't yet exist, so how can we have a plebiscite on a policy that hasn't even been finalised?"

Senator Fielding said a vote on whether or not to have a plebiscite should be properly considered, rather than in the haphazard manner in which it has been dished up.

Had the motion passed through the Senate it was unlikely to be approved by the House of Representatives after pivotal independents Tony Windsor and Rob Oakeshott refused to back it.

But Mr Abbott says he has not given up on Senator Fielding's vote and says he played a "heroic role" in 2009 alerting people to problems with a carbon price.

"I'm conscious of what he said then, and I'm continuing to discuss with him the importance of putting this issue to the people," Mr Abbott said.

"Steve Fielding could be the man that saves Australia from a carbon tax emissions trading scheme that he has already said is not in our national interest.

"I don't think you can assume this matter is settled. All you can say is that discussions are ongoing."