Malcolm Turnbull is challenging Prime Minister Tony Abbott for the liberal leadership.

Mr Turnbull and Foreign Minister Julie Bishop this afternoon asked the Prime Minister to hold a leadership ballot.

He says Mr Abbott has not provided the economic leadership the nation needs.

Mr Turnbull has resigned as Communications Minister.

Former Victorian Premier Jeff Kennett has backflipped on his earlier position that Tony Abbott needed to vacate the top job, saying Mr Turnbull was a selfish, undisciplined individual. 

He spoke with Adam Shand.