New York: An elaborate sting operation has revealed that senior One Nation figures, including Pauline Hanson's chief-of-staff, sought millions of dollars in donations from the US pro-gun lobby to help them water down Australia's gun control laws.

A journalist from news network al-Jazeera, posing as the head of a fake Australian gun lobby group, secretly filmed Hanson's top adviser James Ashby and One Nation's Queensland leader Steve Dickson during a visit to Washington, DC, last year.

Pauline Hanson's chief-of staff James Ashby, pictured left, has been caught meeting with the US gun lobby in secret recordings. Credit:Fairfax Media

While in the US capital, Ashby and Dickson met representatives from the powerful National Rifle Association (NRA) and other conservative groups.

In a conversation with undercover reporter Rodger Muller, Dickson says that he hopes to raise $US10 million from US pro-gun groups.