Kevin Rudd has told his colleagues the next election is winnable as Labor has preserved enough members to be a viable fighting force for the future.

The former leader told Labor caucus in Canberra on Friday that in 2007 the party began with 57 seats and defeated John Howard with a swing of 5.4 per cent.

In 2013 they have 55 seats but a larger number of coalition seats have fallen within three to four per cent, he said.

"This next election is therefore entirely winnable for whoever you elect as your next leader," he said.

"For the campaign that has been fought, I have given it my all but this was not enough and I of course accept full responsibility for the outcome.

"The buck stops with me."

Mr Rudd thanked his cabinet and other colleagues for their efforts, for the honour of serving as their leader and he then remembered fallen colleagues.

He also mentioned himself.

"As in 2010 and 2012, I understand a number of folks in recent days have been free-ranging in their character analysis of me.

"And to those who have made these criticisms, I bear none of you any malice and instead hope for your and our collective success in the future."