Masks could be banned from protests as police blast anti-fascist and anti-Islamic groups

One of Victoria's highest-ranking police officers has blasted the leadership of anti-fascist and anti-Islamic groups for harbouring violent members, and flagged tougher measures including the banning of masks from protests because they promote a "mob mentality".

Assistant Commissioner Stephen Leane said it appeared a bloody clash at the Halal Expo at the Melbourne Showgrounds on Sunday occurred when a group of anti-fascist supporters on their way to a rally in Federation Square noticed the right-wing Party of Freedom peacefully protesting and decided to remonstrate.

He defended the police response to the brawl, and said that once the violence started, officers were focused on separating the battling groups, rather than arresting those responsible for the violence.

A man suffers a nasty head injury at Sunday's anti-Halal protest.

Mr Leane said the investigation into the brawl, which left one anti-Islamic protester bleeding heavily from the head and others injured after being punched, kicked, and beaten with flag poles, was continuing, but that police had little cooperation from the leadership of the respective groups.

He said there was no intelligence to suggest an anti-fascist ambush, and it appeared the attack was not planned. The Halal Expo will be held in Sydney this weekend.

"The anti-fascist group and the anti-Islam group both claim to be peaceful," Assistant Commissioner Leane said.

Police focused on stopping the violence rather than arresting the demonstrators.

"But what we're seeing right across Victoria and right across Australia is that neither side necessarily is peaceful. There's violent protest and violent confrontation every time that they come together.

"We really have to question the motivation of why they're doing it."

Mr Leane said he had spoken to Chief Commissioner Graham Ashton about the need for the state government to implement laws that would ban the use of masks at public gatherings, as it was clear they were used to hide the identity of violent protesters, and protect them if police deployed OC spray.

Demonstrators outside the Showgrounds.

He said the measure would not extend to those wearing religious headdress, and would include common sense measures that ensured those wearing similar clothing as part of their protest - such as the Party of Freedom members on Sunday - would be prevented from doing so.

Mr Leane said Victoria Police worked with unions and other groups to manage their protests, largely without incident, but had been frustrated in dealing with the protest groups who had been involved in clashes, particularly in Melbourne's CBD, Melton, and Bendigo, for the past 18 months.

Of the relationship between Victoria Police and the leadership of the warring protest groups, Mr Leane said: "It's got a long way to go, from both sides."

"There's a sense of entitlement from both sides. There's a sense of entitlement to be able to shut down the city whenever they feel like they can.

"We've got a long way to go in that relationship."

He did not expect the leadership of either group to cooperate in the investigation into Sunday's fracas, and said it was clear "cells" within each movement appeared determined to use their fists to protest.

"There's no doubt that there's elements of both the left and the right ... that see violence as one of the tools they'll use to quell the views of others."

The far-left activists believed to be part of the Halal Expo ambush were from the Antifa group, whose members have not been afraid to resort to violence in the past. The anti-Islam protesters included members of the United Patriots Front and Reclaim Australia, as well as the Party for Freedom.

At the same time as the brawl, hundreds of campaigners filled Federation Square to protest the anti-Islamic movement, which was put back in the spotlight when a United Patriots Front "stop the mosques" banner was unveiled at the Collingwood-Richmond AFL game at the MCG on Friday night.

The scene at Federation Square was much calmer, with UPF reportedly abandoning their plans for a counter-rally.