Melbourne: Australian Prime Minister Julia Gillard on Saturday vowed to fight on after a new opinion poll showed a slide in her popularity and a surge in support for her predecessor Kevin Rudd, who was overthrown by her in a party coup.

The latest Nielsen poll has put her Labor party's approval at only 27 per cent - the lowest for any federal government in almost four decades.

Only 37 per cent approved of her performance.

Voters overwhelmingly preferred ex-PM Kevin Rudd as Labor leader -- 60 per cent to Gillard's 31 per cent -- just days out from the first anniversary of his dumping as leader in a shocking party-room coup.

The Prime Minister laughed off questions about whether she felt secure as leader, according to reports.

"I feel very secure. I have a plan for this country's future and my caucus colleagues are working with me to deliver that plan," she said.

Federal Opposition Leader Tony Abbott says unpopular policies are behind the Government's slump.

"If the Prime Minister wasn't trying to hit Australians' cost of living with this big new tax of everything, if the Prime Minister hadn't completely lost control of our borders, I think that the Prime Minister's position would be much stronger," he said.

Gillard and Abbott are now tied as preferred Prime Minister, while the Coalition leads Labor 59 to 41 per cent on a two-party preferred basis - worse than polling when Rudd was overthrown.

Gillard acknowledged that the carbon tax has damaged her politically, but says she is determined to see her plans through.

"Pricing carbon is the right thing to do for this country's future and I'm going to do it," she said.

But Gillard maintained that she would not be backing away from a carbon tax, resources rent tax and plans to send asylum seekers to Malaysia.

Earlier, Rudd denied reports he was plotting to become prime minister again amid media claims of "screaming matches" with Gillard during a Cabinet room meeting.