Police are investigating claims by former prime minister Tony Abbott that he was headbutted by a same-sex marriage supporter in Tasmania on Thursday.

The prominent ‘No’ campaigner was in Hobart walking towards his hotel when he was approached by a man wearing a ‘Yes’ badge requesting a handshake, Mr Abbott told 2GB on Thursday night.

“I went over to shake his hand and then he headbutted me,” he said.

“He wasn’t very good at it, I must say, but he did make contact. The damage was a very slightly swollen lip.

“I was with a member of my staff. The member of my staff briefly grappled with this guy, and he then ran off swearing his head off, basically.

“But it was a reminder of how ugly this debate is getting.”

Tasmania Police confirmed in a statement that officers were investigating an alleged assault “involving a 59-year-old man from New South Wales” after a formal complaint was made.

The ABC reports that Prime Minister Malcolm Turnbull contacted Mr Abbott to check that he was OK, and also contacted the Australian Federal Police Commissioner.

The alleged attack, which was quickly condemned by the ‘Yes’ campaign on Thursday night, comes amid signs the same-sex marriage debate is becoming increasingly heated.

In a statement, Equality Campaign co-chair Alex Greenwich said: “We condemn the violence against Tony Abbott that has been reported tonight.

“There is never a place for violence or abuse.”

Equality Campaign director Tiernan Brady tweeted: “Let’s be clear, [marriage equality] is about respect. There is no room for disrespect verbal or physical from any side in this journey.”

The alleged incident came amid the postal survey on gay marriage. Photo: AAP

Sally Rugg, marriage equality director at the progressive lobby group GetUp!, tweeted: “SSM is about love and dignity. All violence happening during this plebiscite is abhorrent, including alleged assault on Tony Abbott tonight.”

The former PM had been meeting with ‘No’ campaigners including Tasmanian Liberal senator Eric Abetz on Thursday, a day after he launched an anti-bullying website with Senator Abetz in Launceston.

He said the alleged assault had taken place after he had met with the editor of Tasmania’s The Mercury newspaper.

“I was walking across that Mercury office, just across that beautiful docks area of Hobart towards my hotel,” Mr Abbott said.

“A fellow sung out at me, ‘Hey, Tony’. I swung around and there was a chap wearing a vote ‘Yes’ badge. He says, ‘I want to shake your hand’. I went over to shake his hand, then he headbutted me.”

Mr Abbott recounted the alleged incident in an interview on 2GB with Andrew Bolt and Steve Price.

Asked by Mr Bolt why he had not fought back, he said: “As he was scarpering away, among all the f––k this and f––king that, it was ‘You deserve it because of all the things you’ve said’. I think it was pretty clear that this was, I use the phrase, politically motivated violence.

“It all happened in just a few seconds and the thought certainly went through my mind, but then I thought, ‘No, that just escalates it’.”

This is terrible – violence like this is never acceptable. I'm glad Mr Abbott isn't seriously injured and I've rung him to say so. https://t.co/FkSOUhObgZ

— Bill Shorten (@billshortenmp) September 21, 2017

The attack on @TonyAbbottMHR by a SSM advocate will prove to be the turning point of the yes/no vote and final nail in the yes coffin.

— Prue MacSween (@macsween_prue) September 21, 2017

The former boxer, who repeatedly described the incident as “disconcerting”, told both hosts it had not been the first time he had been attacked while an MP.

“I was actually thumped when I visited the forensic psychiatric hospital in Victoria,” he said.

“One of the hospital patients punched me, as I was later told, because he was under the impression I was his dad.

“This is the first time I’ve been subject to any physical violence for about 10 years.”

He said that the “ugliness” in the debate has not come from the ‘No’ side.

“The love is love brigade isn’t showing a lot of love, I’ve got to say.”