Scott Morrison is deeply concerned by reports Pauline Nation's One Nation asked powerful US lobby groups for $US20 million ($A28m) in funding, in part to help it roll back gun control in Australia.
The prime minister has stressed Australia's gun laws are not being weakened, after the claims emerged through an undercover investigation.
"Australia's gun laws are world's best thanks to (former Prime Minister) John Howard & we will not be changing them," he posted on Twitter.
One Nation's Queensland party leader Steve Dickson and Senator Hanson's chief of staff James Ashby made the case for funding in meetings with pro-gun groups in the US, the investigation by Al Jazeera reveals.
The groups included the National Rifle Association of America and Koch Industries - America's second largest privately held company, which has donated hundreds of millions of dollars to conservative political causes.
One Nation has referred the news report to police and intelligence services.
"Al Jazeera are a state-owned propaganda arm of the Qatari government that supports Islamic extremist groups and are not a legitimate media organisation," the party told AAP.
"The matter has been referred to ASIO and the Australian Federal Police due to concerns of foreign interference into Australian politics in the lead up to the imminent federal election."
The party insists it "strongly supports the rights of lawful gun ownership" and claims Al Jazeera targeted it because of its policies on restricting immigration.
The investigation, broadcast overnight on Monday, features a recording of a meeting in Washington DC last September, captured by an undercover journalist.
In it, Mr Dickson tells NRA officials that for the world to look to Australia as a model for gun control would be "poison".
"If we don't change things, people are going to be looking at Australia and go 'well, it's OK for them to go down the path of not having guns, it's OK for them to go down that politically-correct path'," he says.
"It will poison us all unless we stop it."
Mr Ashby is also heard saying on a separate occasion that $US20 million in donations to One Nation would give the party parliamentary influence in Australia.
"If you had 20 [$US20 million], you would own the lower house and the upper house," he says in the recording.
Electoral commission data from 2017/18 shows the Nationals received just over $8 million in combined donations while the Greens took in almost $13 million. Both parties currently hold more federal seats than One Nation.
AAP has sought comment from the NRA.
Cabinet minister Simon Birmingham called on Senator Hanson to front media on Tuesday to explain the "sickening" report.
He said the idea of rolling back Australia's gun laws seemed remarkable in the aftermath of the Christchurch massacre, in which a lone shooter allegedly motivated by right-wing extremism killed 50 people at two mosques.
The NRA meeting came not long before legislation cleared federal parliament in November banning foreign donations.
Al Jazeera's two-part documentary will be shown on the ABC on Tuesday and Thursday, and is available online.