In Melbourne, violence erupted and hundreds of arrests were made as mostly maskless protesters moved through the city.
Meanwhile in Sydney, a heavy police presence was felt in the city, with hundreds of people gathering in Victoria Park before being dispersed by NSW police.
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Here's everything you need to know about the protests.
Melbourne's anti-lockdown protest.
Violent scenes erupted in Melbourne as 218 people were arrested, 236 fines were issued and and six officers were hospitalised during the city's anti-lockdown protest.
Over 4000 mostly maskless protesters gathered in the city, with many heard shouting "freedom" and carrying signs criticising Victorian Premier Daniel Andrews.
More than 700 police were deployed to enforce COVID-19 restrictions in the area.
"While there were some peaceful protestors in attendance, the majority of those who attended came with violence in mind," a Victoria Police spokeswoman said, according to 9News.
"The behaviour seen by police was so hostile and aggressive that they were left with no choice but to use all tactics available to them."
Officers used pepper spray and tear gas to subdue protestors as they broke through police lines outside Parliament House on Spring Street.
Protestors were also seen throwing objects at police in Flinders Street.
"Seven police officers were injured, including two with suspected broken noses, one with a broken thumb and the others with concussions."
"One officer was also treated at the scene for a cut to his neck that didn't require hospitalisation."
In response, more than $1.1 million in fines are set to be handed down by police and three people were placed in custody for allegedly assaulting police officers.