More than 1000 protesters have brought Melbourne's CBD to standstill in support of asylum seekers on Manus Island.
The Friday night demonstration, which set off from the State Library, has caused major delays for trams and cars as protesters move through the city down Swanston Street.
There is a heavy police presence with dozens of officers lining the street, including some on horseback, blocking the protest from heading towards the city's busiest intersection outside Flinders Street station.
Protesters are holding signs that read: "Peter Dutton kills people" and "End the siege on Manus".
Police earlier said they were aware of the planned action, adding they respect the rights of protesters but "will not tolerate people breaking the law or endangering the safety of the community".
The protest follows the closure of detention facility on Manus Island, where hundreds of men have holed up rather than move to alternate accommodation.