With Mr Rudd due back in Brisbane today, both camps are jostling for numbers, with some ministers stepping up vitriolic attacks on the former foreign minister but others now emboldened to publicly support him.

Ms Gillard has early momentum, with her supporters claiming a solid majority, while the Rudd camp is hopeful of making up ground in the secret ballot.

The Prime Minister has unilaterally called for a vote on her position, to be held at Monday's caucus meeting, following Mr Rudd's snap resignation from Cabinet.

Four Labor ministers - Chris Bowen, Robert McClelland, Kim Carr and Martin Ferguson - have backed a leadership comeback by Mr Rudd and an estimated 30 caucus colleagues are expected to support him.

As the party tears itself apart, senior ministers are intent on crushing Mr Rudd's leadership bid with excoriating criticism and allegations of treachery.

They hope that humiliating him will prevent a deadly two-stage campaign to overthrow the Prime Minister later in the year.

Ms Gillard said she expected to win but if she lost, she would relinquish leadership ambitions.

She called on Mr Rudd to give the same undertaking for the good of the party.

''We can win [the next] election, provided we use Monday's opportunity to end this [disunity] for all time,'' she said.

Asked if she blamed Mr Rudd for derailing her election campaign, Mr Gillard said: ''The 2010 election was sabotaged … we were in a winning position in that campaign until the sabotage that knocked that campaign very, very solidly.''

Leaving Washington for Australia yesterday, Mr Rudd again sought to outmanoeuvre Ms Gillard by outlining key policy areas he would pursue if elected to the Labor Party leadership.

They were education, health care reform, manufacturing, the car industry and business confidence.

Mr Rudd said Labor needed him as leader to ''save the country'' from a Tony Abbott-led government.

Although he is yet to formally declare his bid, Mr Rudd gave a positive assessment of his achievements as Prime Minister and criticised the axing of some of his programs.

''I do not believe that Prime Minister Gillard can lead the Australian Labor Party to success in the next election,'' he said.

He also proposed to reform the ALP and end the power of factions.

''It's about people power,'' he said.

His wife Therese Rein called on voters to lobby their local MPs and senators.

''What ordinary people tell me is that they trust Kevin and they respect him. They know how hard he worked after the 2007 election and in the lead-up to that,'' she said.

Treasurer Wayne Swan built on an earlier extraordinary attack by saying the former leader had ''great weaknesses'' which had not been seen in public.

''The truth is that Prime Minister Rudd was deeply flawed,'' he said.

Mr Rudd's behaviour had become ''increasingly erratic'' when he was prime minister, Mr Swan said.

''There's no doubt he sought to tear down the 2010 campaign,'' he said, while not directly accusing Mr Rudd of the damaging leaks.

''I don't think many people doubt the fact that Mr Rudd, behind the scenes, in the 2010 campaign was quite disloyal to the Labor cause.''

Ms Gillard began her pitch for votes by emphasising her success in achieving policy wins despite the hardship of a minority government.

''We have shown courage in adversity,'' she said.

''I believe I can lead Labor to that [2013] victory, provided that the Labor Party unites and we get on with the job.''

She said it was now evident that there had been a long running destablisation campaign to reach the point where Mr Rudd was about to challenge her.

''There has been a concerted campaign here,'' she said.

The Rudd-led government had descended into paralysis. ''Kevin Rudd as prime minister always had very difficult and very chaotic work patterns,'' she said.

''Having lived through the days of the Rudd government, it became absolutely clear to me that one of the overriding problems of the government that Kevin Rudd led is it was very, very focused on the next news cycle, on the next picture opportunity, rather than the long term reforms for the nation's interests.''

Mr Rudd is basing his leadership campaign on his reputed popularity in the community, urging Australians to lobby their local MP to vote for him.

''It's about people's power, and the people of Australia have a view on the future leadership of their country,'' he said.

Some MPs reported a surge in contact from constituents, with a majority of voters favouring Ms Gillard to remain as Prime Minister.

Ministers who spoke out against Mr Rudd included Mr Swan, Simon Crean, Craig Emerson, Tanya Plibersek, Nicola Roxon and Stephen Conroy.

Ms Roxon said Mr Rudd was not the ''messiah'' who could win the next election for Labor.

Defence Minister Stephen Smith who is backing Ms Gillard, said Mr Rudd had become, in the final days of his prime ministership, ''impossible to work with''.

Dr Emerson, who is acting Foreign Minister, said any plans for Mr Rudd to continue to destabilise Ms Gillard's leadership from the backbench, if he lost on Monday, were ''very, very concerning''.

''It is outrageous, absolutely outrageous, for people to say they will continue to destabilise,'' he said.

''This is a disgraceful plan and Kevin Rudd should renounce it.''

Mr McClelland, who was demoted from attorney-general to Emergency Management in last year's cabinet reshuffle, said Mr Rudd was the party's best prospect to win at the next election, due at the end of next year.

''In circumstances where the party's primary vote has been flat lining for 12 months, we have an obligation to put forward our best leader to the voters,'' he said.

Mr Abbott said the whole affair was a demoralising spectacle that was embarrassing to Australia.

He blamed Independents Rob Oakeshott, Andrew Wilkie and Tony Windsor for giving Labor the support it needed to form government after the 2010 federal election.

''This government only survives because they back it,'' he said.

''Every mistake that this government makes, every day that this … shambles goes on, it is their responsibility.''

He dodged a question on whether he would move a no-confidence motion in the government next week.