'Validated': One Nation eyes cities after historic win

His win over community independent Michelle Milthorpe snapped 77 years of coalition rule in the electorate and marked the first time his party has won a federal lower house seat.

One Nation MP Barnaby Joyce said the party was looking to replicate its success in western Sydney and was already speaking to potential candidates.

"What they've seen is that the polling is not an aberration, it's now been validated by both South Australia and Farrer, there is a strong following out there," he told Seven's Sunrise program on Monday.

"We are very much in the mind for western suburbs of Sydney. I was talking to people from the western suburbs of Sydney ... I was even talking to potential candidates. People are very enthusiastic."

Prime Minister Anthony Albanese said the result was devastating for Opposition Leader Angus Taylor.

"The Liberal Party and National Party made a big mistake legitimising One Nation," he told ABC Radio.

"In adopting many of their policies, but a lighter version of them, and then following that up by giving them preferences, they were saying, effectively, that it was OK to vote vote for One Nation rather than the traditional conservative party."

Mr Albanese said Labor had also been monitoring the result closely.

"There's a lot of people under financial pressure who feel like the system isn't working for them, and that's a message for all political parties in the system."

With the Nationals allowed to run in Farrer due to Sussan Ley vacating the seat after her ousting as party leader, the Liberals' primary vote tanked to 12.4 per cent - down more than 30 percentage points.

Liberal frontbencher Ted O'Brien said the coalition would be looking at lessons from the by-election result.

"What we need to do as a political party is to ensure that we are presenting the policies for the times," he told ABC Radio.

"The problem is not Pauline (Hanson), the problem is the direction of our country. People becoming poorer as a nation, we're becoming more divided."

Mr O'Brien rejected suggestions the Liberals would be open to forming a coalition with One Nation to form a future government.

Mr Joyce also ruled out One Nation forming a larger coalition with the Liberals and Nationals.

"We'll offer supply and confidence on policy outcomes ... and that is not a coalition," he told Nine's Today program.

The result in Farrer could be replicated in certain outer suburban seats, not just regional ones, former Labor strategist turned leading pollster Kos Samaras said.

"Seats like Lindsay (in Sydney's west), I could see that seat could definitely become an interesting contest," the RedBridge director told AAP.

"Every regional electorate that the Nats and the Liberal party hold is on the block," he said.

"If you're getting close to 40 per cent primary vote in Farrer, then it's going to be a lot higher in inland electorates right across the country."

Labor was less vulnerable to a similar reckoning, with Mr Samaras pointing out Pauline Hanson's approval rating was minus 57 with its voters.

"It doesn't mean Labor doesn't have a problem," he said.

"It will lose maybe one or two seats to One Nation.

"Seats like Hunter ... that will be a threat, but it is much easier for Labor to combat One Nation because they are the contrast."