Television images showed officers working to keep the groups apart, but violence erupted. Police responded with pepper spray as rocks, glass bottles and sticks were thrown.

Five police were injured, though not seriously, and two protesters arrested. Victoria Police Assistant Commissioner Stephen Leane described the protesters as leftists and accused them of using violence to get their message across.

“I’ve got no doubt part of their motivation last night was to get as much as they could splashed around the world and feel famous for five minutes,” he said, slamming the waste of resources needed to keep them in check.

Yiannopoulos called the protesters “petulant babies”.

“There was a lot of kerfuffle out front,” he told 2GB commercial radio. “It was not as the newspapers reported ‘a clash between the far left and far right’ it was the left, showing up, being violent to stop freedom of speech.

“The left really showed us who they are. They attack the police, they attacked other people, they attacked journalists – they showed us they are petulant babies.”

Yiannopoulos spoke on Tuesday at a press conference in parliament house in Canberra after being invited by a minor party senator, David Leyonhjelm, despite efforts by the Greens party to ban him.

“Some people who don’t like him are idiots, and violent idiots into the bargain,” said Leyonhjelm, who has been described in the past as a “libertarian purist”.

“I wouldn’t be surprised if they engage in something stupid [in Canberra], but hopefully the security people in parliament are ready for it.”

Yiannopoulos, a conservative firebrand and staunch fan of US President Donald Trump, resigned from right-wing news site Breitbart in February amid a storm triggered by comments in which he seemed to condone paedophilia.

Reviled by his critics as racist and misogynistic, Yiannopoulos casts himself as a gay crusader for free speech who is against “political correctness” in all its forms.