He would ”restore the trust” of the Australian people that she had lost, he told a news conference in Brisbane.
Ms Gillard, who ousted him as PM in June 2010, called the vote following weeks of speculation that he would challenge her for the top job.
Speaking inMelbourneafter Mr Rudd, she asked colleagues for support, stressing she was the right choice.
Mr Rudd resigned as foreign minister at a snap press conference inWashingtonDClate on Tuesday night, prompting Ms Gillard – his deputy before she ousted him as prime minister – to call the leadership ballot a day later.
‘Finish the job’
Mr Rudd won the 2007 election by a landslide and remains popular in opinion polls.
“I want to finish the job the Australian people elected me to do when they elected me to become prime minister,” he said, speaking to reporters inBrisbanejust hours after returning from theUnited States.
He called for a ”truly secret” ballot on Monday and also said that if he failed to win the majority vote from his colleagues, he would go to the backbenches.
”I will not challenge Julia a second time; I will continue to work for my community,” he said.
He focused on the importance of beating opposition leader Tony Abbott in the next elections in 2013. ”Beating Mr Abbott is vital; beating Mr Abbott is doable,” he said.
Ms Gillard, meanwhile, asked voters to look at her record.
”Australians can have trust in me that I am the person to get things done,” she said, referring to Mr Rudd’s remark that her leadership had eroded the trust of the people.
She also stressed that she had worked on ”hard reforms” in her time as prime minister. ”Talk is easy, getting things done is harder and I’m the person to get things done,” she said.
The ruling Labor Party government is struggling to retain voter support and Ms Gillard has been slipping in popularity polls. She leads a minority government which relies on independents for its wafer-thin majority.
Mr Rudd emphasised that his polling figures had remained consistently higher than those of the Gillard-led administration.
But he refused to address a question on the exact number of supporters he had among his party colleagues.
He said he was encouraged by the support, adding that some of his colleagues were ”working on those numbers” while he was there at the press conference.
Political observers say currently Ms Gillard appears to have the support of at least two-thirds of the 103-member Labor caucus.
She said the leadership ballot was not a popularity poll like ”an episode of Celebrity Big Brother”.
“The choice that my colleagues will make on Monday is about who should be prime minister of this nation,” she said.
“It’s a choice about who has got the strength, the temperament, the character and the courage to lead this nation.”