In the latest sign the National Party faces an existential threat from One Nation, polling obtained by the ABC shows its West Australian state leader suffering a 20-point drop on his 2013 election result.

Key points: Polling indicates a sudden spike in support for the One Nation party, particularly in Pilbara

Polling indicates a sudden spike in support for the One Nation party, particularly in Pilbara One Nation may make deep inroads into the National Party vote by the March 11 state election

One Nation may make deep inroads into the National Party vote by the March 11 state election Senator George Brandis' comments on the "mediocre" Qld LNP has given the WA Nationals further reason to fear

One Nation accounts for 16 points of the swing against Brendon Grylls in the vast northern seat of Pilbara, even though the party has yet to nominate a candidate.

Mr Grylls won the seat from Labor in 2013 on a primary vote of 38 per cent.

The polling was commissioned by the Chamber of Minerals and Energy of Western Australia and conducted by the Labor Party's pollster Utting Research. It is based on 300 telephone interviews with enrolled voters in the 17,000-seat electorate between November 1 and 3.

Mr Grylls has drawn the ire of the mining industry for his proposal to levy a $5 per tonne tax on iron ore mined by BHP and Rio Tinto.

But the numbers will spook the National Party because they are eerily similar to those quoted by federal Attorney-General George Brandis in his open mic confession about the failings of the Liberal National Party in Queensland.

He told Victorian Liberal Party chief Michael Kroger: "The thing that is alarming everyone is, as you would expect, the sudden spike in One Nation which is now at about 16 per cent."

In the wake of the federal election, the LNP analysed the One Nation footprint in Queensland using the Senate count, as the party did not stand candidates in every seat.

Then the state-wide One Nation vote was 9 per cent, compared with 4 per cent in NSW and Western Australia. But support for One Nation in seats like Flynn, Hinkler, Wright, Maranoa and Capricornia was over 15 per cent and sat above 10 per cent in seven other seats.

Senator Brandis gave voice to a wide-spread fear in the LNP: "I think there is every reason to believe that [One Nation] will win quite a few seats in the state election."

That election is due in 2018 but Western Australia goes to the polls on March 11 next year and there is now every reason to believe that One Nation could make deep inroads into the National Party vote in that state.

Not just One Nation that poses threat

The Shooters Fishers and Farmers Party recently ended the Nationals' 69-year stranglehold on the NSW regional electorate of Orange on the back of rage against the now-abandoned decision to ban greyhound racing and to force council amalgamations.

The threat to its rural base is causing some federal and state National MPs to question whether the party is suffering from its closeness to the Liberals.

Senator Brandis and others are floating the idea of demerging the parties in Queensland, and in federal Parliament the party is asserting its independence, with two Nationals senators crossing the floor to vote against the Government on the controversial Adler shotgun import ban and three Cabinet ministers abstaining.

But cosying up to the Liberals cannot explain all of the National's woes as the Western Australian branch has long made a point of keeping its distance from its city-based conservative cousins.