Refugee activists have brought traffic at Melbourne's container port to a standstill after unfurling "SOS Manus" banners on Monday morning.
Three protesters climbed light poles above the Footscray Road entry and refused to come down while others unfurled banners and marched on the road.
The activists, protesting against Australia's border regime and to call for an end to the detention of all refugees, also held a large banner that read: "All refugees in detention are political prisoners."
"Today we are taking action against Australia's border policy, which remains open to corporate profits, yet is violently closed to those seeking safety," spokesperson Charlotte Lynch said.
"We support the calls made by refugees and ex-detainees for international sanctions to be placed on Australia until the people on Manus are free."
Refugees from Manus Island refused to leave on October 31 after the PNG Supreme Court ruled the detention centre unconstitutional last year.
Asylum seekers and refugees were provided alternative accommodation, but they feared for their safety in the community and refused to leave when authorities attempted to move them.
One of the climbers, Sid Littlewood, said the advocates refused to go along with the Australian Government's approach.
"We refuse to remain complicit in the Australian government's torture and imprisonment of refugees," he said.
"The bipartisan policy of deterrence relies on suffering and abuse to hold up the fiction of Australia's border. This policy is taking lives, not saving them."
Activists block a Melbourne port container and unfurl banners. Source: SOS Manus
Recent reports suggest almost 200 refugees are set to leave Manus Island and Nauru for resettlement in the US as early as January.
It would also mark a significant increase in numbers from the initial 54 refugees that were resettled in the first round in September.
Under the refugee deal, the US agreed to take up to 1250 refugees - subject to security vetting.
Activists block a Melbourne port container and unfurl banners. Source: SOS Manus
