Three contestants for Lib leadership as Vaile quits

Outgoing defence minister Brendan Nelson has become the third senior Liberal to put up his hand for the party leadership, as Nationals' leader Mark Vaile today joined the former ministers choosing to exit politics.

Mr Nelson announced he will contest the leadership of the federal Liberal Party, following announcements by former environment minister Malcolm Turnbull and health minister Tony Abbott.

Former treasurer Peter Costello - widely viewed as Mr Howard's natural successor - shocked the party yesterday when he announced he would not seek a leadership role in opposition.

Outgoing federal education minister Julie Bishop and former foreign affairs minister Alexander Downer say they have not yet decided whether to stand.

Former workplace relations minister Joe Hockey ruled himself out of the race today.

Addressing the media, Mr Abbott admitted he did not have the best of campaigns but said he had demonstrated "reasonably good people skills" and that he could "give a knock and take a knock".

"I had some tough times on the campaign trail and I would be the last to say that I was prince perfect," he said.

Mr Abbott said he was not going to repudiate the Howard government and declined to offer any new policy directions.

He said he possessed the skill to speak frankly and candidly, without resorting to political spin.

However, he admitted that at times he spoke "perhaps too candidly".

Mr Abbott is a long shot with bookmakers to win the leadership, behind Mr Turnbull and Dr Nelson.