Labor is voting on whether to keep Gillard as party leader or offer another chance to Rudd [GALLO/GETTY]
Julia Gillard, Australia's prime minister, has said she was "very confident" of surviving a leadership challenge from Kevin Rudd - the man she deposed - calling on Labor to unite whatever the outcome.
Rudd, ousted as prime minister in a shock June 2010 party-room coup, will face Gillard in a secret Labor ballot for the leadership Monday after dramatically resigning as foreign minister in a bid for the top job.
Gillard is tipped to win the secret ballot on Monday (late Sunday 23:00 GMT), but many MPs are said to remain undecided.
Gillard said on Sunday she was "very confident of the strong support of my colleagues" and called on her centre-left ruling party to accept the decision and leave their divisions behind.
"I believe Labor, every one of us, will unite after Monday's ballot. We will unite tomorrow and we will get our shoulders to the wheel delivering Labor's programme and plans," Gillard told reporters.
"The important thing is that tomorrow's ballot ends this -- there is a result and following that result everyone accepts it and unites and gets on with the job and I am absolutely confident that will happen."
Rudd came to power in a 2007 election landslide which ended more than a decade of conservative rule, but a series of policy mis-steps saw him lose the confidence of party chiefs and he was axed for the more pragmatic Gillard.
Though he is widely expected to lose Monday's run-off, with just 30-35 votes in the 103-member caucus, Rudd said he had the backing of a number of top cabinet ministers and urged his colleagues to remember his achievements.
He also pledged "unequivocal support" for Gillard were she to win the ballot.
"If Julia is returned on Monday then she will have my unequivocal support between now and the next election, because we have interests way beyond individuals here," Rudd told the Nine Network.
"This thing is bigger than all of us. If I get mowed down by a bus tomorrow - political or physical - the bottom line is this: the party and the government and the country is much bigger than me," he added.
Tony Abbott, the opposition leader, repeated his calls for the minority MPs who make up Labor's fragile coalition government to withdraw their support and force an election.
Abbott would not confirm whether he was planning to bring a no-confidence motion in parliament, saying only: "I think for Australia's sake this government should go."
Monday's vote caps a period of intense turmoil within Labor, brought to a head by Rudd's dramatic resignation as foreign minister in Washington on
Wednesday and his subsequent decision to contest the leadership.
Rudd said he had faced the unprecedented challenge of delivering big reforms on health, climate change and tax while steering Australia through the global financial crisis and grievances about his leadership were not raised with him.
"I was doing my absolute best to run the country and to bring us through the global recession, totally focused on that," he said.
"None of my colleagues, in cabinet meetings or privately, ever said that[there were problems] to me."
Treasurer Wayne Swan launched a scathing attack on Rudd this week as bitter in-fighting descended into open divisions within Labor, describing him as high-handed, autocratic and egotistical.
But Rudd said Swan "at no time ... reflect[ed] any fundamental concern or any significant problem that would require me to change course, do something radically different in order to retain the position of prime minister."
Gillard called Monday's ballot hoping to douse leadership tensions which have simmered since Rudd, still hugely popular with voters, was dumped shortly before the 2010 national elections.