"I realise that my enthusiasm to return to Parliament in the new year had gone and it's time to move on with other aspects of my life and let others pick up the cudgels," Mr Bernardi said at the time.

Loading

He has almost always voted with the Liberals since quitting the party.

Former Law Council of Australia president Morry Bailes, South Australian Legislative Council president Andrew McLachlan and business consultant Michael van Dissel are in the running to fill Mr Bernardi's position.

The South Australian Liberals will hold a preselection ballot in Adelaide on February 1 involving about 300 members to choose who will get the spot.