Scott Morrison declares Liberals will preference Labor ahead of One Nation

Prime Minister Scott Morrison has directed the Liberal Party to put Labor ahead of One Nation on how-to-vote cards at the upcoming election in a bid to defuse growing anger about Pauline Hanson's minor party and its ties to the gun lobby.

Mr Morrison said further revelations from an al-Jazeera investigation overnight - in which Senator Hanson seemed to suggest the Port Arthur massacre could have been a government conspiracy - convinced him to draw a line in the sand on preferences.

Prime Minister Scott Morrison has pledged to preference One Nation below Labor on how-to-vote cards.Credit: AAP

"This is a decision which is based on our strong view about the sanctity of Australia's gun laws and to ensure that at no stage that those things should ever be put at risk," Mr Morrison said at a press conference on Thursday morning.

"It is very important - having been the party that introduced those laws - that we ensure that they are forever protected and there can be no compromise when it comes to those issues or any trading on the issue of those gun laws."

The decision affects Liberal Party preferences only, and does not compel the National Party or all of the Queensland Liberal National Party to place One Nation below Labor.

Queensland LNP members who sit in the Liberal party room in Canberra will have to follow the directive, but those who sit in the Nationals party room will not.

"What the Nationals do is a matter for them, that's a separate issue," Mr Morrison said.

Deputy Prime Minister Michael McCormack said the Nationals had not made a decision on preferences.

"When it comes to preferences, as is the case with every election, the Nationals are a grassroots party and decisions are made at a state and local level. These decisions will be made closer to election day when all the candidates are known," Mr McCormack said.

Mr Morrison has come under enormous pressure to repudiate One Nation at the ballot box on Liberal how-to-vote cards - not only in the wake of the al-Jazeera revelations but following the Christchurch terrorist attack, allegedly at the hands of a white supremacist Australian gunman.

While promising to put One Nation behind Labor, Mr Morrison indicated the Liberals could still preference Senator Hanson's party ahead of the Greens.

"I've always found the Greens to be a real, serious danger to Australia," he said.

"The Greens have opposed us on almost every element of national security legislation we have put into this Parliament. They have actively worked against the safety of Australians."

Mr Morrison said he held off making a decision on preferences because he was

waiting to see how One Nation responded to the al-Jazeera revelations, which resulted from a three-year undercover sting operation.

One Nation officials James Ashby and Steve Dickson, who met representatives from the National Rifle Association, said they were drunk when they discussed soliciting millions in donations from the gun lobby and enthused about unwinding Australia's gun laws.

They were also critical of al-Jazeera and its undercover reporter Rodger Muller, labelling him a spy and repeatedly emphasising that he worked for "a Middle Eastern country" - that being the Qatari government which owns al-Jazeera.

Mr Morrison said he was disappointed with that response, and called the men's behaviour "appalling". He said he consulted party executives and former prime minister John Howard before making a final decision on preferences.

Many voters follow how-to-vote cards handed out by political parties at the voting booth - but they are only suggestions, and every voter has the right to allocate their own preferences as they see fit.

Liberal preferences essentially make no difference to seat-by-seat results as the Liberal Party typically finishes first or second in lower house seats.

However, the decision will prompt a response from Senator Hanson, whose preferences do make a difference, particularly in close Queensland seats.

Senator Hanson was critical of the al-Jazeera "hit piece" but is yet to respond substantively to the revelations in the documentary or Mr Morrison's decision on preferences.