JULIA Gillard has sunk below Tony Abbott as the preferred prime minister for the first time, according to Newspoll.

Ms Gillard is now the most unpopular modern leader since Paul Keating at his worst, according to the latest poll published in The Australian today.

The poll shows that voter satisfaction for the prime minister, who won the job 12 months ago, has fallen to a record low.

According to Newspoll, conducted last weekend in a telephone poll of 1,158 people, satisfaction with Ms Gillard was down two percentage points to 28 per cent, her lowest since becoming leader and a fall of 22 percentage points since she announced the carbon tax.

The poll also shows that dissatisfaction with her has jumped to a high of 62 per cent, or seven points up in the past two weeks.

The last PM to sink that low was John Howard in June 1998, after announcing plans for a GST but no details, and then again in March 2001 when he had GST teething-problems.

When asked who would make the better prime minister, 41 per cent said Mr Abbott and 39 per cent preferred Ms Gillard. One in five said they did not want either of them.

Mr Abbott's disapproval rating remained steady - at 52 per cent.

It was the first Ms Gillard had come off second best in the preferred PM stakes.

Her government is faring no better with its primary vote crashing to a record low for Labor of 30 per cent.

The coalition's support is steady at 46 per cent, with the Greens remaining at 11 per cent.

The Australian says that based on second-preference flows at the last election, the coalition has maintained its election-winning lead over Labor of 55 to 45 per cent on a two-party-preferred basis.

Yesterday Ms Gillard insisted the carbon tax was the right thing to do. "It's the equivalent of saying 'eat your vegetables', I suppose," she told Sydney radio.

A separate online poll from Essential Research said if Mr Rudd were reinstated as leader, the ALP would get a 13-point primary vote leap and enjoy a two-party lead of 53-47.

If the Liberals returned to Malcolm Turnbull as leader, the Coalition vote would rise five points and they would take a 59-41 two-party lead.

Despite the poll slump Ms Gillard says she is determined to push on with her government's agenda, including a carbon tax.

"This is a tough reform and it may get even tougher, before it gets easier," she told ABC Television.

When asked about voter preference for Kevin Rudd, the man she toppled to become prime minister a year ago, Ms Gillard said: "My eyes are firmly trained on the future and what is right for this country."

Ms Gillard insists that once carbon pricing is in place, people will see how the system works and its benefits.

"We're a long way from that, that's why I think we're in a tough period now and there may be some further tough periods ahead," she said.

"But ultimately I believe Australians will see the need to price carbon."