The South Australian parliament has a new speaker after the Labor opposition backed legislation moved by crossbench MPs to put an independent in place.

After the bill passed, Dan Cregan, who recently quit the Liberal Party, was elevated to the role, replacing Liberal Josh Teague in a late-night vote less than six months out from the next state election.

As Mr Cregan took the chair, Premier Steven Marshall left the House of Assembly chamber.

Mr Cregan, a first-term MP, said it was his sincere belief that having an impartial speaker would improve democracy in the state.

“I will well and truly serve this parliament. It is my hope that I will bring honour to the proceedings here,” he said.

“I have great respect for the government. I have great respect for the opposition.

“I hope that I will discharge my functions clearly, with great respect for all members present.”

Mr Cregan quit the Liberal Party only a week ago, in a major blow to Mr Marshall’s re-election prospects.

His decision plunged the Liberals further into minority government in SA, with the party holding 22 seats in the 47-seat lower house.

Labor has 19 seats and six are now held by independents, including four former Liberals.

-AAP