Liberal MP Julia Banks has spectacularly quit the party to sit on the crossbench, hitting out at self-interested "right wing reactionaries" who dumped Malcolm Turnbull as prime minister.
Ms Banks' move slipped the coalition further into minority government and came as Prime Minister Scott Morrison talked up its stability and clear direction while he briefed reporters on his timetable for a surplus budget in April and a May election.
"The Liberal Party has changed, largely due to the actions of the reactionary and regressive right wing who talk about and to themselves rather than listening to the people," Ms Banks told the lower house on Tuesday.
The newly independent Victorian MP said axing Mr Turnbull had been a selfish act.
"The coup was aided by many MPs trading their vote for a leadership change in exchange for their individual promotion, pre-selection endorsements or silence," the MP for Chisholm said.
"Their actions were undeniably for themselves, for their position in the party, their power, their personal ambition - not for the Australian people who we represent."
The coalition had a one-seat majority of 76 seats in the 150-member House of Representatives under Mr Turnbull but the loss of Wentworth and now Chisholm means Mr Morrison leads a minority government in the 150-seat parliament.
Former prime minister John Howard said the coalition had been in worse positions than this.
"The Liberal Party is obviously going through a difficult time at the moment, but I am still convinced that we can win the next federal election," he told ABC TV on Tuesday.
"I obviously don't know much about Julia Banks, except that I did campaign for her in her marginal seat of Chisholm and she, like me, owes a lot to the Liberal Party."
Mr Morrison stuck to his guns in question time, ignoring questions about Ms Banks' decision.
But other Liberals spoke up, with former foreign minister Julie Bishop saying she was "saddened" by Ms Banks' move.
"She was a strong, sensible centre female politician in our party," Ms Bishop said at an event in Sydney.
"But I'm sure knowing her as well as I do, she would have thought long and hard about how she could best serve the interests of her electorate."
Queensland Liberal MP Luke Howarth said Ms Banks had been feeling down since Mr Turnbull was dumped.
"It does look messy," said the MP, who backed Peter Dutton in the leadership spill.
"But the fact is in hindsight I think Scott Morrison is the right choice for us right now."
Human Services Minister Michael Keenan said Ms Banks' defection doesn't change much in parliament because she has promised she won't vote for no confidence motions.
The coalition government had already slipped into a minority on Monday, after independent Kerryn Phelps was sworn into parliament to replace Mr Turnbull.
