Queensland Liberal National Party MP Chris Davis has quit parliament after a tumultuous relationship with the government.

The Newman government has lost a fifth MP since its resounding 2012 election win.

Its vast majority shrunk again on Friday when maverick MP Chris Davis resigned from parliament without a courtesy call to the premier.

The first-time MP and former Australian Medical Association Queensland president was sacked as assistant health minister last week after clashing with colleagues over changes to the state’s corruption watchdog and new individual contracts for doctors.

Dr Davis said he had stood on some powerful toes and was partly demoted because he raised concerns with the premier about looming changes to political donations.

His dissatisfaction came to a head on Thursday night, when he told parliament he couldn’t support his government’s policy to remove caps on political donations and raise disclosure thresholds.

He left the chamber before the laws were voted on.

While Dr Davis says his demotion was a catalyst to his immediate departure from politics, the accumulation of controversial legislation had weighed heavily on his conscience.

At the same time as his resignation, he released polling showing the majority of voters in his Stafford electorate backing him and believing he had been unfairly treated.

“The passage of recent government legislation affecting critical aspects of our democracy goes contrary to my value system and that of the majority of my electorate,” he said in a statement on his website.

“I would never have stood for parliament on such a platform, nor do I believe I would have been elected.”

The LNP will now have another by-election battle, after suffering a 17 per cent swing against it in the Redcliffe poll just three months ago.

Mr Newman found out about Dr Davis’ resignation about the same time as the media and says he would have appreciated a phone call.

He says because there were no health or family reasons for the departure Dr Davis should have served out his whole term.

“We have done everything we can to accommodate his concerns within the team,” he said.

“We have no problem with members speaking out on occasions when they are passionate about things.

“The LNP is a team that permits people to cross the floor and he could have done that last night.”

Mr Newman has two candidates in mind to run in Stafford but said it will ultimately be up to the party.

Maxillofacial surgeon Dr Anthony Lynham has already been selected for Labor.

Opposition Leader Annastacia Palaszczuk says Dr Davis’ resignation was a vote of no confidence in Mr Newman’s leadership.

The Labor leader downplayed her party’s chances of regaining Stafford, which the LNP holds by a 7.1 per cent margin.

“We need to restore honesty and integrity back into Queensland,” Ms Palaszczuk said.

Clive Palmer Tweeted that his party will contest the by-election but he is calling on the premier to hold a general election instead.