One of six men protesting on the roof of the Darwin Immigration Detention Centre has harmed himself.
An Immigration Department spokeswoman confirmed six asylum seekers climbed on to a roof at the centre.
The ABC has been told the men are from Afghanistan.
The men held up a sign which read “Please help us to get out of cage” and “tell Human Rights we are here like animals”.
The men say they have been held in detention for 18 months.
One of the men appeared to be bleeding.
The department says the men are being encouraged to cease the protest action.
It says they have access to healthcare and psychological support.
Another man being held at the centre staged a rooftop protest last week.
Rohingyan (Burmese) man Habib Rahman told the ABC he was found to be a genuine refugee in May last year but has not been given security clearance to leave detention.
He says he wants to be removed to another country if Australia will not accept him.