SYDNEY (AFP) - Australian police are investigating a brawl between a senator and a top aide that left blood on the walls of the Australian Parliament.

Police and parliamentary authorities are looking into a Wednesday night (Feb 13) altercation between 70-year-old Senator Brian Burston and a staff member for populist Senator Pauline Hanson.

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

In a statement, Mr 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 Ms Hanson gaining outsized influence in Australian politics - has been banned from Parliament.

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

Ms Hanson, leader of the One Nation party, made light of the harassment allegations by saying she was 64 years old 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 Mr Burston of offering sex to cheer her up. He denied the allegations.