Queensland Premier Campbell Newman has sacked his Assistant Health Minister Chris Davis for criticising State Government policies.

Dr Davis is a former Australian Medical Association state president and first-term MP for Stafford.

He first clashed with his own party over contracts for senior doctors, but in the past few weeks he has also publicly questioned proposed changes to the Crime and Misconduct Commission (CMC).

Dr Davis commissioned a poll of his electorate and threatened to cross the floor and vote against the legislation.

He ultimately did not cross the floor, saying he was happy with amendments put forward by the Attorney-General.

But on Tuesday afternoon Mr Newman said Dr Davis's position was "untenable".

"[His] recent actions have breached the long-established Westminster convention of Cabinet solidarity," Mr Newman said in a statement.

"I thank Dr Davis for the contribution he has made in the role, and look forward to his continuing contribution to the Government's efforts on behalf of his constituents."

Dr Davis said he has paid the price for speaking out, and that was the reality.

Queensland Opposition Leader Annastacia Palaszczuk says the sacking of Dr Davis showed Mr Newman does not tolerate criticism.

"It's very sneaky for the Premier to sack this Assistant Health Minister an hour before the [federal] budget is delivered," she said.

"It shows how weak the Premier is and it also shows that this Premier, Campbell Newman, will not tolerate anyone else's views other than his own."

Treasurer Tim Nicholls has defended the timing of the announcement.

"I was in Townsville yesterday, only returned back to Brisbane at about 11:30 today. The Premier had a series of engagements. The earliest date that we could meet and the earliest time was later this afternoon," he said.

"It was done as soon as we possibly could after reviewing the week's events on Monday."