Three asylum seekers have begun a rooftop protest at the Villawood Detention Centre in Sydney's west.
There are also claims of confrontations involving police at the centre's perimeter fence and that fires have been lit.
The ABC understands the protesters on the roof are all male and have been held at the facility for about a year.
"There are fires burning in the ground of Villawood detention centre, it's outside stage three," said George Georgiadis, a protester outside the centre.
"The protesters broke through the Commonwealth barrier and risked fines to go and meet the guys on the fence.
"The detainees have been throwing chairs over the fence. There has been shouting and there's fires burning as we speak."
The Department of Immigration has not returned the ABC's calls.
Earlier today Immigration Minister Chris Bowen denied Villawood detainees were on a hunger strike following the suicide of a fellow inmate.
Iraqi man Ahmad al-Akabi, 41, was found dead in his quarters at the detention centre on Monday night.
His was the second suicide of a detainee at Villawood since September.
http://www.abc.net.au/news/stories/2010/11/17/3069256.htm?section=justin