One Nation has referred Qatari-owned media outlet al-Jazeera to the Australian Federal Police, after a years-long sting operation caught senior party figures seeking multimillion-dollar donations from the US gun lobby.

The investigation - in which a reporter set up a fake pro-gun organisation in order to mingle with top-level figures in the United States' National Rifle Association - secretly recorded two senior advisers to One Nation leader Pauline Hanson during their visit to Washington in September last year.

James Ashby is often referred to as One Nation leader Pauline Hanson's right-hand man. Credit:Dominic Lorrimer

In one recording, Queensland One Nation leader Steve Dickson says his party would "have the whole government by the balls" if it were to receive millions from the NRA.

The report comes as the government considers whether to preference One Nation last on its how-to-vote cards at the upcoming federal election in light of the Christchurch terrorist attacks, due to One Nation's anti-Islam rhetoric.