Former prime minister Tony Abbott's sister, Sydney councillor Christine Forster, had her jacket ripped as she tried to enter a fundraiser surrounded by hundreds of Manus Island detention protesters.
Riot police formed a human chain to shield guests arriving for a Liberal Party fundraiser from several hundred Manus Island protesters who had formed outside the Friday night event.
Immigration Minister Peter Dutton and Mr Abbott attended the event.
Cr Forster had to be helped through the crowds by police and had her clothes torn in the crossfire.
The protesters were calling for the Immigration Minster to restore services to the now-closed Manus Island detention centre and bring the remaining asylum seekers to Australia.
The Australian Government had officially closed the detention centre on the Papua New Guinea Island on October 31.
'It was shocking and dangerous'
Cr Forster said a man screamed abuse at her and she grabbed her partner Virginia Edwards by the hand and tried to avoid the situation.
"Basically then a melee broke out, it was a riot," she said.
"It was an extraordinary situation, it was very unpleasant, it was dangerous for everybody, it was an aggressive, awful, scary situation.
"I'm not a federal politician so what happens in Manus Island is not my brief, but I'm a local City of Sydney councillor and I don't want to ever have this kind of stuff happening in my electorate."
Cr Forster said people should able to walk into an event "unmolested, unassaulted and unattacked".
"Not being spat on, not being abused in my electorate of the City of Sydney, in my beautiful, wonderful city of Sydney and this was a terrible attack," she said.
"It was shocking to me and it was dangerous. These people put not only Virginia and me in danger, but they put the police who were looking after us in serious danger and they put themselves in danger by the way they were reacting.
"People were trying to punch us, people ripped the jacket off my back … If you want to make your political protest, anyone can make a political protest anywhere in Australia, but you don't do it like that."
She said the protesters went too far.
"It was a very unpleasant, unnecessary, dangerous situation that those people put everybody in," she said.
"It was a situation that I have never been in and I would never choose to be in ever again. It's my favourite jacket and it's shredded sadly and it was shredded off me from behind.
"It was a very volatile and extraordinarily surprising situation to me."
Protesters call for Manus refugees to be brought to Australia
On Friday, refugees and asylum seekers on Manus island told the ABC they were "extremely scared" as workers tore down fences around the compound.
The Papua New Guinea Government also put up a notice warning "force may be used to relocate those who refuse to move voluntarily".
Protesters outside the Liberal Party event at Australian Technology Park in Eveleigh spoke on loudspeakers and harassed and berated guests, with police forced to intervene several times.
Hundreds of protesters came with whistles, pots and pans, shouting "Abbott, Dutton, blood on your hands" and "Shame on you" to the guests who made their way through through the crowd.
Activist Lily Campbell said she was protesting because Mr Dutton and Mr Abbott were "responsible for the siege on Manus Island right now".
"I think every refugee should be brought here and should be granted asylum in Australia," she said.
"I can't believe the state it's got to on Manus Island," another protester, Margaret Walters, said.
"It's just atrocious … they should never have been put in an offshore detention camp."
Hundreds of people also marched through central Melbourne calling on the Federal Government to assist refugees at the Manus Island detention centre.
The rally began at the State Library before demonstrators marched along Swanston Street.
There were no arrests.