For the second consecutive time, former Prime Minister Kevin Rudd backed out on Friday of challenging current Prime Minister Julia Gillard as leader of the Australian Labor Party.

He explained his decision to unchanged circumstances in the party that would lead to his leading again the party.

Mr Rudd echoed the interview of Workplace Minister Bill Shorten over Fairfax radio that there would definitely be no ballot next week or anytime before the Sept 14 election.

Another indicator of Ms Gillard being confident there would be no further challenge to her leadership of the ALP is her planned two-day trip to Indonesia for bilateral talk after next week.

The unions, which are the PM's main support outside parliament, agreed that now is not the time for a comeback for Mr Rudd.

"If Kevin Rudd was there, he won't be elected because the newspapers, the media will be turning around and making an attack on Kevin Rudd," Transport Workers Union chief Tony Sheldon said.

Mr Rudd's second turnaround, however, earned the ire of Opposition frontbencher Joe Hockey who accused the former PM of using weasel words.

"It's a circus - this is groundhog day ... He said previously there are no circumstances, now he says I believe there are no circumstances," Adelaide Now quoted Mr Hockey.

Political pundits said the use by Mr Rudd of the word "believe" opens the door to him reassuming the top ALP post once circumstances change.

However, for now, all eyes are on the Newspoll survey slated to be released on Tuesday if Ms Gillard's numbers would improve after the rumblings within her party have stopped, that is temporarily.

RELATED STORIES