DISASTROUS new polling has shaken Julia Gillard's support within Labor as more MPs believe the party needs a "circuit-breaker".

Senior ministers yesterday conceded the leadership issue and disunity was destabilising the government, blaming Kevin Rudd, The Australian reports.

Supporters of Mr Rudd, however, blamed the poll slump on the Prime Minister's decision to call the longest election campaign in Australian history and poor decisions by her and Wayne Swan.

The Treasurer will answer his critics today in a fiery speech to the Australian Workers Union conference, where he will declare Labor must win the next election to ensure fairness and opportunity. He will defend his record as Treasurer and the fact the economy grew in spite of the global financial crisis.

Addressing the Australian Workers Union national conference last night, Ms Gillard praised her "good friend" Mr Swan, who had returned from a meeting of G20 finance ministers in Russia.

"In that room, when they looked for leadership, they looked to Wayne Swan, a man honoured as the world's best treasurer," she said.

Supporters of Ms Gillard are expressing a growing anger towards Mr Rudd over his high profile in recent weeks and are blaming him for constant leadership speculation. The Australian has been told Gillard supporters believe more poor polls for the government in coming weeks will increase pressure on some MPs, who are "becoming more and more convinced they need a circuit-breaker".

"There is no doubt that a lot of caucus members are now reconsidering their position," one caucus member said. "Effectively someone is holding a gun to their head and saying either put me in charge or I'll blow the place up."

Labor frustration boiled over yesterday after a Nielsen poll in Fairfax newspapers showed a five-point drop in Labor's primary vote to 30 per cent, the Coalition's vote up 4 per cent to 47 per cent and Tony Abbott leading Ms Gillard by four points as preferred prime minister.

The poll also showed Mr Rudd outranked Ms Gillard as preferred Labor leader by 61 per cent to 35 per cent, although Malcolm Turnbull led the Opposition Leader as preferred Coalition leader 58 per cent to 35 per cent.

While Gillard supporters are blaming Mr Rudd for the government's position, a Rudd supporter said the "elephant in the room" was Ms Gillard's decision to name the election date for September 14.

Rudd supporters continue to insist "nothing is happening" and Mr Rudd is sticking by his commitment after last year's leadership ballot not to challenge.

At the weekend, Mr Rudd said he was "not interested" in the leadership and the issue should be put in "cryogenic storage".

A series of senior ministers yesterday blamed instability and division for the slump in support.

Regional Affairs Minister and former party leader Simon Crean said the poll was a "wake-up call ... you can't gild the lily".

"It's where we've been making important progress forward, this seems to suggest back," he said.

Industry Minister Greg Combet said "there is no sugar-coating it, it's a bad poll today, there's no doubt about it". Trade Minister Craig Emerson said Labor needed to "cut out the diversions and distractions and focus on what matters to people, like jobs".

Dr Emerson said the government had been "talking about ourselves, not talking about the issues that really matter to the Australian people, such as jobs. We need unity of purpose. And a government that doesn't show unity of purpose will fall in the polls."

Another Labor MP said the calling of the election was focusing voters minds and reinforcing negatives about the Prime Minister in relation to the carbon tax. But a key Gillard supporter said the poll was a "rogue", disputing the large drop in Labor support in South Australia at a time when there was major internal division in the state Liberal Party.

The poll came after a week where the government was under sustained pressure over the decision to walk away from the budget surplus and the failure of the mining tax to meet budget revenue forecasts.

A Newspoll conducted for The Australian at the start of the month put Labor's primary vote at 32 per cent and the Coalition at 48 per cent, suggesting the government's steady improvement in voter support in the second half of last year had come to an end.

The two-party-preferred vote matched the Nielsen poll, the Coalition leading Labor 56 per cent to 44 per cent.

Ms Gillard yesterday refused to comment on the polls. "I don't do commentary on opinion polls and I'm focused here today on my plan for Australian jobs," she said.

Mr Swan has faced internal criticism after a poor performance in parliament last week and there has been speculation that the government needs to improve the selling of its economic message.

In an address to the AWU national conference on the Gold Coast today, Mr Swan will rally his key support base and declare the government can win the election.

"We're now facing one of the toughest and possibly most important elections in many years," he will say.

"Many of the usual pundits have written us off. My advice is to not listen to them. There's no sure thing in a two-horse race, especially when one of the jockeys is called Tony Abbott. We can win. We have to."

He will tell the conference: "I think Australia is on the cusp of something really big, but only if we have a government that has a real economic and social vision for Australia. I often think to myself, if only we'd got our chance when things were booming.

"We wouldn't have wasted the boom years the way John Howard and Peter Costello did. But whilst we all would have preferred the global financial crisis never happened, we should feel extremely proud of the things we have achieved together."

Dr Emerson agreed the government could rebound from its current position.

Communications Minister Stephen Conroy said the poll was taken at a time when there was "lots and lots of backgrounding going on, lots and lots of speculation going on. I mean, that can't possibly help".

AWU national secretary Paul Howes, a backer of Ms Gillard, said his union supported her 110 per cent and denied Labor MPs had been wrong to dump Mr Rudd. He said Ms Gillard was a "street tough" prime minister who had overseen one of the most productive periods of government in the history of federation.

Bill Ludwig, the union's national president, praised Ms Gillard. He said when the union needed help to combat the Newman government's public sector job cuts, "we turned to our friends in Canberra to help".

Opposition Treasury spokesman Joe Hockey said Mr Rudd would be a band-aid: "The problem is Labor. Julia Gillard, Kevin Rudd, tweedle-dum, tweedle-dumber: it doesn't matter."

Read more at The Australian.