Victoria Police arrested more than 400 protesters at an anti-lockdown protest outside Parliament House in Melbourne's CBD, where capsicum spray was used to control the crowd.
Hundreds of people took part in the demonstration on Tuesday, with police encircling protesters at the corner of Spring Street and Bourke Street to try to prevent them from moving into other parts of the city.
Despite the easing of coronavirus restrictions, protestors chanted "freedom" and called for the resignation of Premier Daniel Andrews.
Victoria Police said 404 people were arrested and 395 penalty notices were issued.
Some were fined for not wearing a mask, others were fined for breaching the 25-kilometre travel zone and for breaching public gathering directions.
Victoria Police said in a statement that a female senior sergeant was taken to a hospital with a suspected broken arm following an arrest.
Police said others were charged with assaulting police and failing to provide their name and address and six people were taken into custody.
All of the others were arrested, fined and released.
Victoria Police said it was disappointed to arrest a large number of protestors who "showed disregard for the safety of the broader community and the directions of the Chief Health Officer (CHO)".
"Victoria Police will not hesitate to fine those who clearly and blatantly breach the Chief Health Officer directions," a spokesperson said.
Some protesters accused police of using unnecessary force while breaking up the demonstration.
A man wearing a red Make America Great Again hat said he was protesting against "government tyranny".
"[I'm protesting against] them trying to bring in social credit scores, forced vaccines, and track and trace everywhere," he said.
When asked what evidence he had for some of those fears, he said: "It's all over the internet, if you want to not be fake news for five minutes and go look it up."
The man said he had done nothing wrong by protesting and would fight the $1,600 fine he received from police.
Another protester who was fined by police said he felt the use of pepper spray was disproportionate.
