Pauline Hanson's chief-of-staff James Ashby has been banned from parliament after an ugly physical fight with United Australia Party senator Brian Burston.
Senate President Scott Ryan said he made the decision after reviewing footage of the clash between the two men outside a dinner at Parliament House on Wednesday night.
"I have exercised my authority to revoke Mr James Ashby of his pass to access the building and prohibit him from entering the building for the time being," Senator Ryan told parliament.
The upper house's presiding officer said the video showed Mr Ashby behaving inappropriately towards a senator.
Mr Ashby says he respects the decision and has surrendered his pass but called for a probe into the event.
"There must be a full investigation of this matter, the allegations that preceded the altercation and a range of other issues regarding the alleged treatment of female staff that may be relevant to this matter," the staffer said in a statement.
Senator Burston admitted smearing blood on the door of Senator Hanson's office after the clash, which happened after a function at which the two men were seated on the same table.
"Whilst I do not recall the incident of blood on the door I now have come to the conclusion that it was myself and I apologise for the action," the One Nation defector told senators.
Mr Ashby's suspension from parliament is the latest escalation in a bitter feud between Senator Hanson and her former ally.
Tensions erupted after Senator Hanson on Tuesday night used parliamentary privilege to accuse an unnamed senator of sexually harassing at least six staff.
Senator Burston outed himself as the mystery alleged culprit, telling News Corp it was "bullshit", going on to claim he left One Nation after being sexually harassed by Senator Hanson.
The One Nation leader has laughed off the allegations, saying she's "not that desperate".
Australian Conservatives senator Cory Bernardi congratulated the Senate president on taking swift action against Senator Hanson's senior staffer.
"It concerns me because unfortunately Mr Ashby has a track record in this place. I hope that 'time being' is a very long time," Senator Bernardi said.