Former prime minister Kevin Rudd confirmed on Friday he will challenge his successor Julia Gillard to lead Australia's ruling party, saying she had lost voters' trust and would crash at the next election.

Rudd, who quit as foreign minister while in Washington this week, arrived back in Australia a day after Prime Minister Gillard called a ballot for Monday to decide who should lead the Labour party.

"If we are honest to ourselves, all the indications are we are heading to the rocks at the next elections," he said, with polls due in 2013.

"Rightly or wrongly, Julia has lost the trust of the Australian people, and starting on Monday I will start restoring that trust.

"That is why I have decided to contest the leadership of the Australian Labour Party." But while he remains popular with voters, Rudd seems likely to lose the party vote, according to media tallies of the 103-member Labour caucus.

So far, at least 20 ministers have publicly declared for Gillard as the divisive rift has plunged Labour into crisis and descended into a series of ugly personal attacks.

However, Rudd emphasised the achievements of his government between 2007 and 2010, before he was abruptly removed by Gillard in a party coup following a series of policy mis-steps and bitter disputes over his leadership style.

"I want to finish the job the Australian people elected me to do when I was elected by them to become prime minister," he said, adding that if he lost on Monday he would retire to the backbenches and not take on Gillard again.

"I believe that with the right Labor team we can meet the challenges of another global crisis and see off the threat of a Tony Abbott government," Rudd said, referring to the conservative opposition leader.

Rudd has never forgiven his one-time deputy for ousting him, observers say. Gillard now leads a minority government that relies on the support of independent and Greens MPs.

Labour is badly lagging Abbott's conservative opposition ahead of the elections due next year, with polls suggesting Gillard's administration would be dumped by the electorate if an election were held the next day.

Prior to Rudd announcing his challenge, Gillard said the Labour ballot was not a popularity contest but about who could govern best.

"It is a choice about who's got the strength, the temperament, the character, the courage, to lead this nation, who's got the ability to get things done even in the face of adversity," she said.

"This is not an episode of 'Celebrity Big Brother', this is about who should be prime minister."

Since he resigned as the country's top diplomat amid intense leadership speculation, Rudd has been savaged by senior cabinet ministers who accuse him of undermining the party for personal gain.

He hit back on Friday, telling people not to believe the scathing criticisms that suggested 'Kevin Rudd is the Antichrist incorporated, and if not the son of Satan, at least the grandson of Satan'.

"It's quite plain to me that what I see from the faceless men is the same shock and awe tactics that I seem to remember being deployed during the leadership coup during June 2010," he said in Brisbane.

Rudd urged voters to take matters into their own hands and 'pick up your telephone, speak to your local members of parliament, tell them what you think, jump into the media, tell them what you think'.