One Nation candidate David Farley swept to victory in the sprawling southern NSW electorate of Farrer on Saturday night, ending the coalition's 77-year reign in the federal seat.
With more than 80 per cent of ballots counted, Mr Farley had claimed more than 57 per cent of the two-candidate-preferred vote to comfortably beat independent Michelle Milthorpe.
It is One Nation's first federal lower-house election victory since the party was founded by Senator Hanson in 1997.
After declaring the anti-immigration party was coming for more lower house seats, the One Nation leader put no limit on her goals for the next federal election.
"It's not up to me to put a number on that ... it's up to the people of Australia," she told Sky News on Sunday from Albury, standing in front of a private plane recently donated by billionaire mining magnate Gina Rinehart.
"Do I offer you what you're looking for? Can I deliver? Yes I can."
Former Nationals leader turned One Nation MP Barnaby Joyce also suggested the political earthquake would spread.
"Western Sydney here we come," he said.
The by-election was triggered when long-time MP Sussan Ley resigned after being ousted as Liberal leader by Angus Taylor in February.
Support for the coalition crumbled, down to 12 per cent of the primary vote for the Liberals and less than 10 per cent for the Nationals.
Ms Ley secured more than 43 per cent of the primary vote when she won the seat a year earlier.
Shadow treasurer Tim Wilson did not rule out forming a minority government with One Nation in order to defeat Labor at the next election.
"It all comes down to what Australians put up," he told ABC TV.
"I want to stop the Albanese government from continuing to wreck Australia."
Deputy Liberal Leader Jane Hume conceded trust with voters had been broken due to the coalition splitting twice and said it would take time to rebuild.
But Ms Ley said it would be wrong to attribute the result to the coalition ruptures and urged the Liberal leadership to accept the loss with humility as voters "never get it wrong".
She parroted Mr Taylor's catchcry of "change or die", which he deployed after February's leadership spill.
"Three months later, the result in Farrer demonstrates that statement to be far truer today than it ever was then," Ms Ley said.
Treasurer Jim Chalmers described the result as a "bloodbath" and said it showed the coalition would have to join One Nation to compete.
"There's no future coalition government, I think, without One Nation in it," he said.
Labor chose not to contest the by-election.
Farrer comprises more than 126,560sq/km and fills out the southwest corner of NSW.
Its largest population centre is Albury, which sits on the NSW-Victoria border.
The race, which became a two-way competition between a minor party and an independent, signals a broader shift in voting away from the major parties.
In the 1960s, more than 70 per cent of Australians would vote for the same party in every election.
By 2025, that number fell to just one in three, according to the Australian Election Study.
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