Pauline Hanson's chief of staff, James Ashby, is under investigation for flying his boss around Queensland without the proper pilot's licence.

Key points: ABC understands Civil Aviation Safety Authority is investigating James Ashby's flying of the light aircraft

ABC understands Civil Aviation Safety Authority is investigating James Ashby's flying of the light aircraft Plane is registered as recreational aircraft, which means it cannot be flown for commercial purposes

Plane is registered as recreational aircraft, which means it cannot be flown for commercial purposes Mr Ashby has spoken publicly about flying Pauline Hanson around in the plane

The ABC understands Mr Ashby is being investigated by the Civil Aviation Safety Authority (CASA) for flying the Jabiru J230 during the 2016 election campaign.

CASA has declined to confirm or deny whether any investigation is underway.

If found guilty, Mr Ashby faces fines and could lose his licence.

The ABC understands Mr Ashby only holds a recreational pilot's licence and the plane is registered as a recreational aircraft.

That means it cannot be flown for commercial purposes or in controlled airspace above major airports.

Mr Ashby described the investigation as a "political witch-hunt".

"I will comply with CASA's request for documents, however this is just a further waste of taxpayers' money where their findings will result in the same outcome as previous investigations," he said.

The plane is plastered with a stylised image of Senator Hanson, and Mr Ashby used it to fly the One Nation leader around Queensland in 2015 and 2016.

Sorry, this video has expired Vision of James Ashby flying the plane surfaced last year.

In 2015, Mr Ashby boasted in a radio interview about piloting the then-candidate around for her commitments.

"I've made that commitment to her that I will fly her wherever she wants to go," he told ABC Sunshine Coast.

"We're off every weekend at the very least, we pick a spot, there's guest appearances, general invites that she wants to be a part of. We just jump in the plane.

"It's a Jabiru J230 … we've got it licensed as a light sport aircraft, it's two seats."

A recording of that interview was seized by CASA investigators yesterday.

Mr Ashby also said in the interview the plane was owned by, "a particular member of One Nation", but the bigger question is who paid for it.

That is being investigated by the Australian Electoral Commission, after allegations surfaced last year that it was secretly donated to One Nation by businessman Bill McNee.

Mr Ashby said in the 2015 recording it had been bought a few months prior.

"It's a great piece of machinery, I know when Pauline was looking at the prospects of a plane she was looking for something Australian-made, so we bought a plane that was made in Bundaberg," he said.