One Nation leader Pauline Hanson has said there are "a lot of questions" about the Port Arthur massacre that left 35 people dead in 1996.

In footage captured by an undercover al-Jazeera journalist, Senator Hanson and a group of other people including James Ashby, her chief of staff, discuss the massacre.

"An MP said it would actually take a massacre in Tasmania to change the gun laws in Australia," Senator Hanson says.

"Haven’t you heard that?" Senator Hanson asks al-Jazeera's Rodger Muller, who was pretending to be a representative of Gun Rights Australia, a fake gun lobby group created for al-Jazeera's investigation.