Bernardi says it's 'safe bet' he'll retire

The Liberal Party will have an extra senator by the end of this term, with independent Cory Bernardi saying it was a "safe bet" he would retire within three years.

Senator Bernardi deregistered his Australian Conservatives party on June 28, meaning the ex-Liberal senator's South Australian seat would go back to the Liberals should he retire via a casual vacancy.

"I think that's a safe bet," Senator Bernardi told ABC TV when asked on Thursday whether he would retire.