Australian Conservatives federal leader Cory Bernardi has lashed out at his former South Australian colleagues, accusing them of white-anting his start-up party from within by considering joining the Liberal Party.

The party's South Australian leader, Dennis Hood, announced on Monday he was quitting to join Premier Steven Marshall's newly-elected Liberal government.

It was later revealed that Mr Hood had been encouraged to consider the move by his Conservatives colleague Robert Brokenshire, who was up for re-election at this month's poll.

With the count of Legislative Council votes yet to be finalised, Mr Brokenshire, a former Liberal minister, appears unlikely to be returned.

On Monday, Mr Bernardi expressed disappointment at Mr Hood's departure but said he bore his former colleague no ill will.

However the Senator has now told Sky News that the defection has left him feeling dejected and that he suspects it had been under active consideration prior to the election.

"My wife said to me during the state election campaign, 'who are these people working for, the Australian Conservatives or the Liberal Party?'" he said.

Mr Hood has denied discussing any move with the Liberal Party until the week after the election.

But Senator Bernardi expressed doubts over his former colleague's claims.

"There's been reports that the state Liberal President told senior Liberals that it was likely the Australian Conservatives would be joining them after the election," he said.

"It feels like I've been white-anted from within."

Dennis Hood and Robert Brokenshire are both former members of Family First. Both joined Australian Conservatives last year, when the two conservative parties united in a merger.

Australian Conservatives MLC Robert Brokenshire says members need an extra sitting week. ( ABC News: Nick Harmsen )

Mr Bernardi did not name Mr Hood or Mr Brokenshire directly, but expressed disappointment at his state team.

"I invested a lot in the two people running the campaign and my team, the Australian Conservatives team, worked overtime. We put money into it and we did our very best," he said.

"But as I said, some things have come to light, including preference deals, including candidates.

"We agreed to have 10 candidates, then they asked for 20, I agreed to that and then they announced 33.

"And some of those candidates, apparently, I've since been told were given to us by the Liberal Party.

"And clearly I put too much faith and trust in others and that won't happen again."

Mr Brokenshire rejected those claims.

"It's unfortunate comment," he said.

"There were no discussions before the election. It was as simple as that."

Dennis Hood has said Mr Bernardi's party would have 'no impact' in SA politics. ( ABC News )

Dennis Hood has also denied any suggestion that discussions were under way prior to the election.

"There is no truth whatsoever to the suggestion," he said.

"Utterly false and without basis."