A Julia Gillard backer says Kevin Rudd's looming challenge should not be compared to Paul Keating's double spill to secure the top job.
Paul Keating had two cracks at unseating prime minister Bob Hawke in 1991.
The Rudd camp was talking up Mr Keating's two-step rise to power but said it was a flawed argument, Environment Minister Tony Burke told Sky News.
"With Paul Keating it was a massive difference. You had a caucus that didn't know what he would be like as Prime Minister," Mr Burke said.
"Everyone knows what it would be like to work with Kevin."
There's speculation that Mr Rudd may push for multiple leadership ballots.
Mr Burke said it was "deeply offensive" to subject the party to such pain.
"It's all very well if you're a senator or if you're on more than five per cent or getting ready to retire ... but have the courage to say that to someone out there working hard in a marginal seat.
He said Mr Rudd's challenge was about a popularity contest, not governing.
Mr Burke said as a prime minister Mr Rudd had been uncontactable.
"Even if you rang Kevin's mobile, it was answered by a staffer," he said, adding that ministers are able to easily get Julia Gillard on the phone.