South Australia's crossbench MPs are hailing their coup to ensure state parliament is always ruled by an independent speaker as a "huge step forward in improving our democracy".
The constitutional change, dubbed "extraordinary" by Premier Steven Marshall, was backed by Labor and a number of independents in a late-night sitting in the state's lower house.
It was then followed by a separate motion which ultimately installed Dan Cregan, who only quit the Liberal Party last week, as the new speaker.
Mr Marshall said he had never seen anything like it in his 12 years as an MP.
"Within minutes the parliament decided not to only change the constitution of South Australia with virtually no consultation whatsoever and install a brand new speaker," the premier told radio 5AA on Wednesday.
"It think it was an extraordinary scene."
But Opposition Leader Peter Malinauskas told state parliament Mr Marshall had become totally distracted by the collapse of the Liberal Party around him.
"The Liberal Party is imploding in on itself," he said.
The changes approved in the House of Assembly will now go before the upper house for final approval.
But independent MP Frances Bedford, who introduced the bill which requires the speaker to quit any party affiliation, said the change would improve parliamentary behaviour and standards and was long overdue.
"Only by having a truly independent umpire in parliament can we improve parliamentary standards and behaviour," she said.
"This bill is a huge step forward in improving our democracy. It will raise our standing in the community and restore faith in the work of this place."
Fellow independent Geoff Brock said the bill implemented a system for umpiring parliament long in place in the United Kingdom.
"This is a very significant reform. It adopts a principle long in practice in the UK," he said.
"Only by having an independent speaker can South Australians have full confidence in their democracy, particularly at time of real emergency when additional scrutiny of executive power is badly needed."
After winning the vote on the floor of the house, Mr Cregan was officially sworn in as speaker at Government House on Wednesday.
In a statement, he said there was a new spirit of independence in the parliament and he was humbled to serve.
"I did not expect to be serving in this role," he said.
"However, at a time when emergency powers are being widely exercised, I hope I can bring a fair, balanced and impartial approach.
"If the change to our constitution passes both houses, I believe it will be a very significant reform with lasting consequences that benefit our democracy for generations."
