The men, who have been seeking visas for more than a year, are refusing to eat to press their demand for the process to be expedited.

A 33-year-old Iranian asylum seeker was taken to hospital on Wednesday, his ninth day of the hunger strike, to receive medical attention.

Refugee Action Collective spokeswoman Daniella Olea said the man returned to the centre that same day and resumed the hunger strike.

"[More] people are willing to join him on the strike. I wouldn't be surprised if it does keep going," she said. "It's reaching boiling point."

Ms Olea, a regular visitor to the centre for the past year, said a lack of information for the detainees as to when they would be granted visas had led to them taking strike action.

"There's no communication," she said.

"No one knows how long they'll have to wait. The [federal government] doesn't have to give a time frame so tensions are reaching quite high.

"Six months ago when the asylum seekers were moved to Broadmeadows their hopes were up because it's called an 'immigration transit' centre.

"They were quite hopeful to go into community detention, or get a visa. But in the past few months people are tired, angry and desperate and it's reached a point where some of them are going to extremes.

''There have been many accounts of self-harm. They're all on medication because they don't sleep; it's not a healthy environment," Ms Olea said.

A spokesman for the Department of Immigration and Citizenship confirmed the hunger strike and said the men were being monitored closely.

"Food and water is available to detainees at all times; we encourage them to eat," he said.

"The protest will have no effect on the outcome of their cases."

The spokesman said the men had access to appropriate levels of health care and support.

A candlelight vigil was held for the men on Wednesday night outside the centre with about 50 people attending to lend support.

Ms Olea said the men were aware of the protest outside the centre and were thankful.

"It was really positive for them and for the people outside to know there was a connection."

She said the Refugee Action Collective would continue to visit the detainees and continue its campaign.