Former prime minister Kevin Rudd has urged his Labor colleagues not to "haul up the white flag" before the September election, calling on them to "campaign their hearts out" and claiming that Tony Abbott's pitch to voters is based on "three core lies".

In an interview with ABC's 7.30 on Thursday, Rudd declined to repeat his recent pledge that there were "no circumstances" in which he would return to the Labor leadership, saying instead that he would "not be challenging" and that he accepted the decision of the caucus in the last leadership ballot in February 2012.

After a week in which prime minister Julia Gillard has been criticised by some backbenchers for not making Labor's political case clearly enough, Rudd said that the prime minister, every member of the Labor Party and Rudd himself should be "campaigning our hearts out". With 100 days until the election, he said they still had a chance to persuade voters.

Making his own case against Abbott, he claimed the Coalition leader's pitch to voters was based on "three core lies" - that he could stop asylum seeker boats, that Australia had a "crisis" with its levels of debt and that Abbott himself had suddenly transformed into a policy moderate.

"He says he will stop the boats and he will send them back to Indonesia, that is an absolute lie, he knows that. The Indonesian government made that clear through their ambassador in the course of the last week or so," Rudd said.

"The second premise is that he says this country has a debt and deficit crisis - that also is a lie, three credit ratings agencies around the world say Australia almost uniquely has a triple a credit rating."

And Rudd said that "after 20 years in parliament, 19 years as one of the most extreme right wing politicians the conservative party has thrown up", Abbott was asking voters to believe that "in this 20th year he has suddenly become a policy moderate. He can wear pale blue ties to assuage people to some point, but a leopard never changes his spots."

Rudd rejected angry criticism from colleagues about his recent high profile and public interventions, accusing them of trying to create "alibis for defeat".

"It is completely wrong for people in our national political life to be on about constructing alibis for defeat when our responsibility on behalf of the people we represent and the parliament of Australia is not just to devise a strategy for victory but to implement that strategy as well."

"We have a phenomenally strong record on the economy, we on the basis of our economic record deserve re-election. My job through until polling day is to argue that case for the Labor Party," Rudd said.

Rudd will campaign on Friday morning in two Victorian seats in Geelong, where Ford has announced it is going to close its manufacturing plant in 2016.

Gillard will be in Melbourne holding a "summit" on the future of the Australian car industry with her ministers, unions and car-makers, convened after the announcement of the Ford closure.

Rudd will visit Labor's most marginal seat of Corangamite, held by Darren Cheeseman, who in February 2012 called on Gillard to resign because she could not take the party forward.

The other, Corio, is held by Richard Marles with a margin of 13.5%. Marles stood down from his job as a parliamentary secretary after the botched attempt to return Rudd to the leadership in March.

"I think it's plain wrong to walk away from any of these seats and that's why I'm coming down to make it absolutely plain that I will be working with these guys in the front line to do everything possible to ensure we get over the line," Rudd told the local paper, the Geelong Advertiser.

"I'm down there to campaign to get them both re-elected and I'm serious about that ... they are good friends of mine.

"I've known them for years, they have been strong supporters and I'm not in the business of conceding ground that we cannot retain these two seats."

But Rudd has also issued a statement saying there were "no circumstances" in which he would return to the Labor leadership.

Labor struggled to contain ill-discipline during parliamentary sittings this week after a Newspoll showed its primary vote had dropped to just 30%, with the Coalition leading 58% to 42% once preference flows have been calculated. With just two more sitting weeks before the election, at least two long-serving MPs Daryl Melham and Alan Griffin have packed their offices so they don't have to return to Canberra if they lose their seats.

The two Victorian backbenchers issued a statement welcoming Rudd's visit and detailing the community events he would attend - a morning tea and a school visit.

"I welcome Kevin's visit to Geelong. Kevin has always been popular in Geelong and it's great to have him back. I see this as an important part of the campaign to win Corangamite and Corio and that is important in terms of winning the election" Marles said.

"Kevin will be welcomed by the community as someone who visited Geelong many times." Cheeseman said.

Less than three months ago Gillard addressed mounting leadership speculation by calling a ballot, which Rudd did not contest.