Opposition Leader Peter Dutton says he takes responsibility for the Liberal Party's astonishing loss at the Aston by-election on Sunday.
The Liberal Party's defeat in the outer-Melbourne electorate was the first time in more than 100 years that an opposition party has lost a seat to the government in a by-election.
During the campaign, Mr Dutton said the result would be a "verdict on the leaders, no doubt about that".
He conceded to ABC's Insiders that he had failed his own test.
"I accept responsibility and I'm the leader of the party. I was there last night to do that. I agreed to come onto the show this morning knowing that if you win, lose or draw, you need to front up," Mr Dutton said.
But Mr Dutton said he still deserved to remain Liberal leader.
The party has suffered a projected six per cent swing against it, after already going backwards at the May election while the seat was held by former Liberal minister Alan Tudge.
It leaves the party holding just three of the 26 seats across Melbourne.
Mr Dutton said the Liberal Party had lost ground in Victoria under different leaders since John Howard, and that the party had work to do to rebuild its base there.
But he said the "fundamentals" of the party would not change.
Former prime minister Malcolm Turnbull this morning rebuked the Liberal leader on Twitter, noting the party had seen success in Victoria in 2016, when it won Chisholm with moderate candidate Julia Banks.
"Jeez Peter — just tell the truth. Victoria is a small-l liberal state and the Liberal Party egged on by the Murdoch media has moved further and further to the right," Mr Turnbull wrote.
Prime Minister Anthony Albanese said the result was a mark against Mr Dutton's approach.
"He's just saying no to everything and not being a part of any solution. He's become an observer of Australian politics rather than a participant," Mr Albanese said.
"And last night, just as he is saying no to all of the policies that are being put forward, Australians said no to him. And the people of Aston said no to him."
Coalition points to brand damage caused by Liberal infighting
Nationals leader David Littleproud said ultimately the by-election boiled down to local issues, but that the Liberals suffered at Aston due to a "personal character assassination" of Mr Dutton.
"I thought [that] stooped to a level that Australian politics shouldn't. We've got to be better than that," Mr Littleproud told Channel Nine.
But Mr Littleproud accused the Victorian Liberal branch of doing "everything they could locally there to trash their own brand" by not running a candidate from the area, and following party infighting at the state level over the attempt to expel Liberal MP Moira Deeming for participating in an anti-trans rights rally that was attended by neo-Nazis.
The Nationals leader said Mr Dutton remained "by far" the best choice to lead the Liberal party.
Mr Dutton said his party would analyse its loss at Aston and what drew some voters towards Labor for the first time.
But he agreed that the Liberal brand in Victoria had "suffered terribly".
"There are issues that we need to address within the division here in Victoria. That is a statement of the obvious and that has been going on for a long time," Mr Dutton said.
