"Being silent is a green light for dictatorship," a speaker told the crowd.
"Never give up Hong Kong, we've got your back. Fight for freedom, fight for democracy."
A handful of people began shouting at the group but were escorted away from the rally by police, who had an increased presence compared with an event held at the same location on Friday night.
Friday's pro-Hong Kong rally turned ugly when a group of at least 100 pro-China protesters arrived.
Videos posted to social media show the rival groups pushing and shoving one another before being separated by police.
The event was estimated to have attracted about a thousand people at its peak.
A Victoria Police spokeswoman confirmed two men were interviewed on Friday in relation to unlawful assault, before being released pending summons.
"We respect the right of the community to express their views peacefully and lawfully but will not tolerate those who break the law or engage in antisocial or violent behaviour," she said.
Victorian opposition leader Michael O'Brien said the violence was unacceptable.
"This is Australia, we're a democracy. You're allowed to have your say, you're allowed to protest peacefully but we draw the line at violence. It's just not on," he told reporters.
"I understand people are passionate about these issues in Hong Kong but you've got to play by the rules of this country and that is peaceful protest not violence."
Meanwhile, a pro-China march has been held in Sydney, with videos showing hundreds descending on the city's Town Hall, chanting "Long Live China" and singing the Chinese national anthem.
"If Hongkongers don't love Hong Kong, get the f*** out. If you don't love China, you're our enemy. Isolate them. Get the f*** out," some protesters reportedly chanted.
Rallies have also been held in Adelaide and Brisbane and follow months of demonstrations in Hong Kong.
Hong Kong has been plunged into its biggest political crisis since the former British colony's return to Chinese rule in 1997, with a wave of protests against a now suspended extradition bill which would see people sent to mainland China for trial in Communist Party-controlled courts.
The protests, which started in April have now transformed into broader demands including the resignation of Hong Kong's embattled leader Carrie Lam and calls for a "free Hong Kong".