Cory Bernardi has told colleagues he is considering quitting parliament amid speculation he could rejoin the Liberal party.
The Guardian understands the South Australian senator, who quit the Liberals in 2017 to form the Australian Conservatives party, is closely considering his future, and has canvassed the option of leaving the Senate before his term expires in 2022.
Bernardi is said to be weighing up how he can best be “effective” in the parliament in his time remaining after he left open the possibility of rejoining the Coalition party room.
If he quit before his term expired, he would open up a casual vacancy for the Liberal party in South Australia.
Bernardi has long been a proponent of Australia adopting nuclear power, and could be a key vote in the parliament if the government decided to remove the ban on nuclear that exists in the Environment Protection and Biodiversity Act.
He has not yet had any discussions with the prime minister, Scott Morrison, about rejoining the party, but told Sky News on Tuesday that he was open to the idea.
“I am open to having a conversation with the government about how best I can support their agenda, but I’m not compromising myself,” he said.
“I do want to see this government succeed, so I’ll think about how best I can do that.”
The government’s Senate leader, Mathias Cormann, said it “was a matter for the Liberal party in South Australia” whether Bernardi rejoined the Liberals.
“I would always like to see additional members in the Senate join the Liberal-National team, of course,” he said.
If Bernardi rejoined the Coalition, the government would have 36 votes in the Senate, needing only three more from the crossbench to pass legislation.
He has indicated he will back the government’s three-stage income tax cut plan and has voted consistently with the Coalition since he defected in 2017.
At the 18 May election, his Australian Conservatives party won just over 16,000 first preference votes, compared to 53,000 for One Nation and 33,000 for the United Australia party.
When he defected, fellow Liberals accused him of embarking on a vanity project, and a senior conservative, Peter Dutton, called the move a “betrayal”.
“I think people will be angry about any defection, angry about the betrayal of the Liberal party values,” Dutton said.
Then deputy prime minister, Barnaby Joyce, accused Bernardi of not being able to “handle the heat of the kitchen”, and senior South Australian moderates called on him to quit.