Chief Commissioner Shane Patton says his officers had no choice but to use non-lethal weapons to defend themselves from an angry mob that came armed and appeared intent on attacking them.

At least nine officers ended up in hospital after being pelted with projectiles, punched and kicked by some members of a 4000 strong crowd who turned out to protest the city's COVID-19 lockdown.

The mostly unmasked protesters let off flares, yelled slogans and blasted music as they moved through the CBD.

More than 200 people were arrested including some on remand for previous crimes. At least 19 will be taken to court rather than issued with fines in excess of $5000. Two people will face assault charges.

Mr Patton said he was nothing short of disgusted with the conduct of some in the crowd.

"What we saw yesterday ... was probably one of the most violent protests we've seen in nearly 20 years," he told reporters on Sunday.

He said many in the crowd came armed with projectiles that were hurled at police and it was clear they were there not to protest for personal freedom but to "confront and attack".

Eight of the nine wounded officers have since left hospital but one remains for further examination. Injuries included blows to the body, cuts, bruises, suspected broken noses, one possible incident of loss of consciousness, and one leg injury.

"It appears to us that they came in with an intention of that violence," Mr Patton said.

"This wasn't a group that had a specific leader. It seemed that it was angry men ... between 25 and 40," he said, "who were intent on causing this mayhem, intent on being involved in this criminal activity.

"I just hope it doesn't result in the mass spread of COVID-19. The risk that those people have now posed to the rest of the community, by their conduct yesterday, was disgraceful and selfish."

Mr Patton also revealed 48 people have been fined almost $5500 each over an illegal engagement party in Caulfield North, including the future bride and groom.

That number is expected to rise with eight other attendees yet to be interviewed.

The rest of the people at that party were children. They've been warned and won't receive fines.

NSW police also arrested 47 people and fined more than 260 in relation to protests on Saturday.

They issued 137 tickets after stopping around 38,000 cars approaching Sydney city, while a 32-year-old man who allegedly assaulted an officer was arrested and charges were expected to be laid.

The constable was taken to hospital for head and neck injuries.

More than 2000 people also gathered in Brisbane City Botanic Gardens to rally against the lockdown and vaccine measures.

Australian Associated Press