A physical clash has rocked Parliament after Pauline Hanson accused a senator of harassing staff, and Brian Burston said she “rubbed her fingers up his spine”.

Senate President Scott Ryan has stripped One Nation staffer James Ashby of his parliamentary pass and banned him from the building in the wake of his physical altercation with Senator Brian Burston last night.

Mr Ryan said he had reviewed CCTV footage of the incident to inform his decision.

“Senators must be free to go about their work in this building,” he said.

“Passholders are granted access to the building on certain conditions of behaviour, amongst others. These conditions are in place to protect all occupants and facilitate the work of members and senators.

“The video footage that I have reviewed records the reported incident between Senator Burston and Mr James Ashby last night. It shows inappropriate conduct by a passholder towards a senator.”

Mr Ashby has not lost his job. He simply cannot enter parliament.

Meanwhile, in another bizarre twist, Mr Burston has admitted he was the one who smeared blood on the door of Pauline Hanson’s office - even though he claims he cannot remember doing it.

“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 sincerely apologise for that action,” Mr Burston said.

Earlier today, Mr Ryan revealed the parliament’s top officers and the Australian Federal Police were investigating last night’s unseemly stoush between Mr Burston and Mr Ashby, who is Ms Hanson’s chief adviser.

“We will be looking into this matter as a matter of urgency,” Mr Ryan said.

The inquiries began as Senator Brian Burston, a hand in a bandage, claimed he had been defending his wife from Pauline Hanson’s close staffer James Ashby.

Mr Burston, who quit One Nation last year, clashed with Mr Ashby in the foyer of Parliament House only a few metres outside a Minerals Council dinner attended by Prime Minister Scott Morrison in the Great Hall.

The scuffle followed claims last year Mr Burston, now with Clive Palmer’s newly relaunched United Australia Party, had told a female staffer he would “f*** her” to improve her mood.

He has firmly denied the claim made last year.

More recently, Mr Burston has accused Ms Hanson of suggestively touching him and offering to sleep with him.

Ms Hanson has rejected the allegation as false.

The tensions erupted late last night when Mr Burston and wife Ros encountered Mr Ashby.

An eyewitness today told news.com.au only about six other people were in the foyer at the time.

He said there was some shoving between the two and Mr Burston grabbed Mr Ashby’s mobile phone and threw it away.

The witness said Mr Burston and his wife walked away towards the entrance to the Senate side of Parliament House, and Mr Ashby followed with his mobile phone videoing them.

“Ashby was laughing wildly, baiting him,” said the witness.

Closer to the security entrance to the Senate wing, Mr Ashby was close to Mrs Burston, still videoing, said the witness.

Mr Burston said in a statement he had referred the encounter to the Australian Federal Police and said he had acted “in self defence” to protect himself and his wife.

“It is clear that James Ashby has set up Senator Burston to look badly for political purposes, all in breach of parliamentary rules,” said the statement.

An image supplied by Mr Burston appeared to show his hand with blood on it from cuts the senator said happened when he tried to grab Mr Ashby’s phone.

“I told him to f*** off,” Mr Burston told The Australian, adding that he tried unsuccessfully to grab the phone.

“I lost it,” the senator said.

“I grabbed him and I pushed him up against the wall.”

Mr Ashby said the senator’s claims were false and he had been trying to take images of Ms Hanson leaving the same function when Mr Burston attacked him.

It came after Mr Burston, outed himself on Wednesday as the unnamed senator accused by Ms Hanson of sexual harassment.

Ms Hanson had in parliament on Tuesday accused an unnamed senator of sexually harassing at least six staff, and using taxpayer funds for payouts to keep some of the women silent.

Mr Burston said on Wednesday he was the man referred to, telling The Daily Telegraph it was “bull***” and one of the reasons he left One Nation was because of sexual harassment from Ms Hanson over two decades.

The One Nation leader laughed off Mr Burston’s allegations last night, telling Paul Murray Live she’s “not that desperate”.

“I cannot stop laughing over this, I think it’s hilarious. I’m sorry I should be serious about it but I can’t stop laughing about it,” Ms Hanson told the Sky News host.

Mr Burston alleged Ms Hanson first sexually harassed him 20 years ago, claiming she ran her fingers up his spine at One Nation’s first AGM in 1998.

“I had federal police protection that were watching my back and I’m sure if they’re watching my back, they’re watching his back,” Ms Hanson said.

“I’m sure if I wanted to rub my hands up a man’s back, I’m sure it wouldn’t be on the stage with federal police and 2000 people there in the room, so it’s a load of rubbish Paul.”

Ms Hanson also lashed suggestions she’d propositioned the senator three years ago.

“There’s no truth in that whatsoever that I would ask Brian Burston to stay the night,” she told Sky News.

“You know Paul, a lot of men have tickets on themselves and I tell you what Brian Burston, don’t go out in Canberra, it’s very windy tonight.

“I might be 64 (years old) Paul but I tell you what, I’m not that desperate.”

“Right back when we had our first One Nation AGM at the Rooty Hill RSL (in 1998), that was the first time she hit on me,” he said, of the unwanted attention.

He claimed Ms Hanson “rubbed her fingers up my spine” while listening to the national anthem and she’d propositioned him after he was elected in 2016 at her home in Queensland and Canberra.

But Ms Hanson denied all claims.

“I wouldn’t go near him with a barge pole,” she said.