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 left the service in suburban Canberra.
But senior government figures were not so reticent.
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 said.
Cabinet colleague Christopher Pyne called on Senator Bernardi to quit parliament.
"The honourable course is for him to resign his seat and for him to recontest it as an independent," he tweeted.
Related reading
Bernardi to overshadow parliament start
Trade Minister Steve Ciobo was dismissive of the senator's ability to take up the fight against Labor.
"With one or two exceptions he's never laid a glove on the Labor party," he told Sky News.
"Every time he's been in the headlines it's been about criticism of his own parties."
Cabinet minister Kelly O'Dwyer said Australians had no tolerance for parliamentarians on ego trips.
"They want to know that parliamentarians who are sent to Canberra are focused on their interests and focused on the broader national interest," she told ABC TV.
"I think that people would feel that their trust has been violated if somebody stood for a particular political party and then left that political party, particularly so soon after an election campaign."
Mr Dutton doesn't believe other coalition MPs will follow Senator Bernardi out the door even though he's tipped to announce the formation of the Australian Conservatives party when he publicly reveals his future to the Senate later on Tuesday.
Nationals backbencher George Christensen, a fellow conservative, said Senator Bernardi had never asked him to leave the Liberal-National Party.
"At this point in time I'm very loyal to (leader) 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."
Deputy Labor leader Tanya Plibersek said the senator's departure was a sign the Liberal party had hit "absolutely rock bottom".
"If you hand your lunch money over to the school bully, and then one particular day you get lucky and that bully's not at school, I tell you there'll be some other bully lining up to take your lunch money," she told reporters.
Greens senator Sarah Hanson-Young said Senator Bernardi was "a rat leaving a sinking ship" and predicted his views would be rejected by their fellow South Australians.
"I know he's got name recognition in his own lunchbox," she said.
Share
