An Iranian asylum seeker who has been on a hunger strike for 50 days in detention on Nauru has been evacuated to an undisclosed hospital on the Australian mainland.
Supporters say the man, known as Omid, began the hunger strike as a protest against the lack of information on how long his processing would take.
Refugee advocate Pamela Curr says she fears Omid is at risk of organ failure.
A statement from the Department of Immigration says he "will be returned to the Nauru Regional Processing Centre as soon as he is deemed medically fit to travel".
But in the meantime, Ian Rintoul from the Refugee Action Coalition says the detention centre has gone into "total meltdown".
"The last 48 hours there's just been a series of self-harms, attempted suicides - just pandemonium," he told ABC radio's PM program.
"There've been scuffles between Wilson Security and asylum seekers, between asylum seekers and Salvation Army workers, and an endless stream of self-harm attempts.
"People have moved, asylum seekers have been removed from the detection centre. Five of them were still being held somewhere outside of the detention centre.
"There are accusations that people have been taken out of the detention centre, have been beaten by Wilson Security guards."
Mr Rintoul says besides Omid, there are 18 asylum seekers who have been on a hunger strike for more than a week.
"Another man is on his 30th day of hunger strike and the others are between eight and 13 days on hunger strike," Mr Rintoul said.
"In the last couple of days other people have joined the hunger strike. I don't know the exact numbers except for those 18."
An Immigration Department spokesperson has confirmed that Nauru police are currently investigating several incidents at the detention centre this week.
PM understands several asylum seekers could be charged with assault.