More than 100 detainees at Sydney's Villawood Detention Centre are on a hunger strike.
Refugee advocates say the detainees are disappointed the Federal Government has talked about change but nothing has happened.
The Department of Immigration says it was made aware of the action yesterday and food and water are always available.
A spokesman for the Department says it has no way of knowing how many detainees are involved.
Ian Rintoul of the Refugee Action Coalition says the detainees are prepared to go without food until their concerns are heard by the Minister for Immigration.
"They've waited a long time for various things, for the Minister to review things, to settle into their new job and still nothing has changed," he said.
"With hunger strikes in detention, people get desperate so... we we've got nothing to lose, we're going to keep the hunger strike going."
Detainees climb Villawood roof in deportation protest
The Department of Immigration has confirmed two Chinese nationals have climbed on to the roof of Sydney's Villawood Detention Centre.
Indonesia tells bombers families get ready
8 years ago