Malcolm Turnbull has given Colin Barnett and the WA Liberal Party the green light to negotiate a preference deal with One Nation that could help save the State Government's grip on power.

Despite only last year declaring Pauline Hanson was not a welcome presence in Australian politics, Mr Turnbull was yesterday given two occasions to express his concern about any preference deal between the Liberal Party and One Nation.

Elements of the Liberal Party are concerned the WA party will break with a convention started by then prime minister John Howard to put One Nation last on how-to-vote cards because of the deep problems facing it at the State election.

We deal with all of the parties in the Parliament, including One Nation — all of the parties. We respect every single member and senator of each and every one of them.

But Mr Turnbull refused to offer advice to Mr Barnett and the WA party, saying it was up to them to decide preference allocation.

“Well, look, the preference allocation is a matter for party divisions and in a State election, it’s a matter for the WA division and the Premier,” he said.

Mr Turnbull said that given One Nation had members in Parliament he had to work with its representatives.

“We deal with all of the parties in the Parliament, including One Nation — all of the parties. We respect every single member and senator of each and every one of them,” he said.

Premier Colin Barnett said he expected One Nation would allocate preferences differently in each seat and rejected claims a deal had been done.

“There will be discussions and negotiations seat by seat, that’s always been the case,” he said.

Mr Barnett said the preference negotiation was a decision for the party.

Camera Icon Pauline Hanson. Credit: South Western Times

Opposition Leader Mark McGowan deflected questions on whether Labor would direct preferences to One Nation, saying it was clear the Liberal Party was considering the idea.

“The Liberals are doing a deal with One Nation. You’ve seen them out to dinner, Norman Moore, Matthias Cormann, senior Liberals having conversations with One Nation,” he said. “I need to put the case for every West Australian to vote Labor. Preferences are a side issue.”

The issue came as it was revealed One Nation’s candidate for Pilbara, David Archibald, disparaged gays and described single mothers as too “lazy” to attract and hold a mate.

In a Quadrant magazine piece in 2015, Mr Archibald wrote that only a “degenerate culture” would permit same-sex marriage.