Australia's conservative opposition has taken an election-winning lead over Prime Minister Julia Gillard's embattled party just weeks ahead of an election, a poll showed on Saturday.

According to a Nielsen survey, the Labor's party's popularity has sunk to levels that prompted Gillard's shock axing of her predecessor, Kevin Rudd, to become the country's first woman leader just five weeks ago.

Gillard's plunging popularity came after she suffered a spectacular reversal of fortunes in the campaign's second week, with damaging leaks and the ghost of a hospitalised Rudd dogging her bid to return the ruling Labor party to office.

Labor's vote slumped to 48 percent against the conservative Liberal/National coalition's 52 percent, the latest Nielsen poll showed, a six percentage point shift away from Gillard's centre-left party.

Labor's primary vote bled six percentage points in the week to 36 percent while the coalition, led by Tony Abbott, gained four points to a commanding 45 percent.

The numbers are similar to those recorded in early June, which Labor considered so dangerous to its re-election chances it took the huge gamble of dumping first-term prime minister Rudd in favour of Gillard, his deputy.

If replicated in the 21 August elections the polling would translate into an election-winning 4.7 percent swing against Labor and put Abbott's conservatives in office.

The survey also confirms public disenchantment with Gillard's policy of seeking guidance on climate change from a "citizens' assembly" of ordinary Australians, with 53 percent saying they opposed it.

By contrast 60 percent said they were in favour of the emissions-trading scheme controversially shelved by Rudd after it was twice knocked back in the upper house, while just 27 percent said they opposed it.

Australia's first female leader, Gillard enjoyed a brief honeymoon with the public, with an initial poll bounce of 14 points after she deposed Rudd in a lightning partyroom coup last month.

But the gloss appears to have come off her leadership, with her preferred prime minister rating down 13 points Saturday to 49 percent, against Abbott's 41 percent.

Her formerly stratospheric rating among women levelled to an even split with Abbott.

The former monk and fitness fanatic was quick to play down his chances, saying he was "very much the underdog in this election campaign" and the polls were volatile, while Gillard called it the "fight of my life".

"What I have always believed was that this was going to be a tough, close contest, the decision will be a photo finish," she said.

Gillard struggled to make headway this week as her campaign was hit with damaging high-level leaks claiming she had opposed popular welfare increases, and widespread speculation Rudd had spilled the information to the press.

Rudd said he would "never comment" on Cabinet discussions and was committed to a Labor victory, as he was hospitalised for gall bladder surgery on Friday.

Rudd's wife, Therese Rein, said he was recovering well and would be "back up on his feet in the next couple of weeks."

Further leaks dominated headlines Saturday, with the Weekend Australian newspaper reporting that Gillard had sent her former bodyguard, Andrew Stark, to critical national security briefings in her place when she was deputy leader.

The prime minister did not deny that she had occasionally sent Stark to keep notes and advise her, but defended him as an experienced officer of the Australian Federal Police.

"I reject as completely wrong and offensive, any suggestion that as deputy prime minister I did not pay due regard to my role in the security of this country," she said.