Renegade Liberal senator Cory Bernardi has told Malcolm Turnbull he is quitting his government to sit on the crossbench as a conservative independent.
Ahead of an ecumenical service to mark the return of parliament for the year on Tuesday, Senator Bernardi reportedly phoned the prime minister to tell him of his intention to quit the coalition.
Mr Turnbull refused to answer questions as he arrived for the service in suburban Canberra.
But Peter Dutton - regarded as the leading conservative inside Mr Turnbull's cabinet - didn't hold back.
"I think people will be angry about any defection, angry about the betrayal of the Liberal Party values," the immigration minister told ABC radio.
Mr Dutton said he didn't believe other coalition MPs would follow Senator Bernardi who is tipped to announce the formation of the Australian Conservatives party when he publicly reveals his future to the Senate later on Tuesday.
Liberal MP Craig Kelly wants Senator Bernardi to think again.
"You can do a lot more inside the Liberal party, working for, arguing those things that you believe in, than actually outside the tent," he told the ABC.
Senator Bernardi's decision is set to dominate the first day of federal parliament for the year.
But cabinet minister Arthur Sinodinos denies it will be a distraction.
"Not if we and the press focus on what's important to our fellow Australians," he said.
Conservative Queensland government backbencher George Christensen said Senator Bernardi had never asked him to leave the Liberal National Party.
"At this point in time I'm very loyal to Barnaby Joyce - I sit within the National Party - it's a party I've been a member of for more than two decades," he told ABC radio.
"I'm going to continue here for as long as the party - and I believe the National Party always will be - in tune with conservative vales and in tune with regional electorates."
Sean Edwards has more reason than most to be angry with his fellow South Australian.
"It would be a gross departure as to - certainly six months into a six-year term - what people would have expected," said the former senator who lost his seat at the 2016 election.
Mr Edwards, who was number five on the SA Senate ticket behind Senator Bernardi running as number two, said he would be disappointed if he left.
"I would prefer to see Senator Bernardi stay within the Liberal party and do the work that all the members that preselected him in preference to members like myself (expect)," he said.
