Australian police are investigating a row between a senator and a top aide that left blood on the walls of the national parliament.

Police and parliamentary authorities are looking into a Tuesday night altercation between 70-year-old Senator Brian Burston and a staffer for Senator Pauline Hanson.

Senator Burston showed off a cut on his thumb following the altercation and, following an initial denial, admitted to smearing his blood on Senator Hanson's parliamentary office door.

In a statement, Senator Burston said he "reported the full matter to the Australian Federal Police" and was asking for a restraining order against the aide.

"This matter is now in the hands of the police," he added.

Aide James Ashby, who had been instrumental in Senator Hanson gaining outsized influence in Australian politics, has been banned from parliament.

Pauline Hanson made light of harassment allegations

The confrontation, which was caught on camera, took place as Senator Burston accused Senator Hanson of years of unwanted sexual advances and she accused an unnamed senator - believed to be Senator Burston - of sexual misconduct.

Senator Hanson, leader of the One Nation party, made light of the harassment allegations by saying she was 64 but "not that desperate".

The pair split politically last year and have feuded since.

Amid the most recent spat, the Guardian reported that a female aide once accused Senator Burston of offering sex to cheer her up. He denied the allegations.