A new opinion poll shows both Prime Minister Julia Gillard and Opposition Leader Tony Abbott are less popular than the leaders they replaced.

The Nielsen poll published in today's Fairfax newspapers says 39 per cent of voters would prefer Kevin Rudd as Labor leader instead of his successor.

And former Liberal leader Malcolm Turnbull is more popular than the man who replaced him: 31 per cent of those polled preferred Mr Abbott as Liberal leader while 37 per cent preferred Mr Turnbull.

The Coalition holds an election-winning 54-46 per cent two-party preferred lead over the Government.

But of some consolation to the Government is the fact the two-party figure is steady despite the carbon tax announcement since the last Nielsen poll.

The poll shows 47 per cent of those polled approved of Ms Gillard's performance while 47 per cent disapproved.

When Ms Gillard replaced Mr Rudd, his approval/disapproval result was poorer - the Nielsen poll at the time showed only 41 per cent approved of Mr Rudd's performance while 52 per cent disapproved.

Mr Abbott's approval/disapproval score is only slightly better than Mr Turnbull's last Nielsen result in late 2009.

Then 41 per cent approved of the job Mr Turnbull was doing and 51 per cent disapproved; now 43 per cent approve of Mr Abbott's performance and 52 per cent disapprove.

Nielsen spokesman John Stirton says both leaders are struggling.

"Politics has always been tough, but over the last year or so it's been much more combative than usual," he said.

"Voters generally don't warm to that sort of approach - it tends to drag both leaders down. And that's really what we're seeing now."

He says Ms Gillard's pre-election promise that there "will be no carbon tax" under her government is coming back to haunt her in the form of rising disapproval figures.

"What that tells us is that she is taking a hit probably over the carbon tax and the broken promise, or the perceived broken promise," Mr Stirton said.

Mr Rudd sought to play down his surge in popularity, saying "polls come and go".

"It was a great honour to serve as Prime Minister of Australia. It's a great honour to serve as Foreign Minister of Australia, and I have really nothing further to add."

Climate Change Minister Greg Combet says the Government is not tackling climate change "because it's easy or immediately popular".

He conceded, however, the carbon tax represents "difficult politics".

"Tony Abbott, of course, is good at scare campaigns. He's wrecked action on climate change once before. The Government is determined that he not wreck it again," Mr Combet said.

"He's on the record as saying the science is 'absolute crap'. He's now trying to pretend that he respects the science, but it's all deceitful."

Opposition environment spokesman Greg Hunt says the figures are in response to the Ms Gillard's broken election promise on the carbon tax.

"I think the Government is suffering because the Prime Minister is fundamentally unreliable - there is a real view that the Prime Minister is out of her depth," he said.

Asked on Perth radio if he would have expected his approval to rise, not fall, Mr Abbott said his job was to hold the Government to account and to prove a "credible alternative".

"Now, some people think I do OK. Some people don't. But I just try to get on with the job," he said.