The Australian Electoral Commission will investigate claims that Pauline Hanson's One Nation party breached electoral disclosure laws by failing to declare a private plane allegedly donated by a Victorian businessman.

In an episode of Four Corners on Monday night, former One Nation treasurer Ian Nelson claimed he urged Senator Hanson and her high-profile chief of staff, James Ashby, to disclose the donation, but was overruled.

Mr Nelson, who has since fallen out with Senator Hanson, alleged Melbourne property developer Bill McNee transferred funds to buy the plane to Mr Ashby and that it was insured in his name.

Mr Nelson said the Jabiru plane, decorated with party logos and a cartoon of Ms Hanson, was used to "ferry Pauline Hanson around" Queensland ahead of the 2016 election.