An Iraqi asylum seeker detained on Manus Island is marking six months since he began a hunger strike in protest at his treatment by centre staff.

Mohammad Albederee said he stopped eating because he was refused proper medical treatment after he was badly beaten by security guards.

He was taken to Port Moresby for medical treatment but said he spent the visit in a motel under constant guard and was brought back after 12 days.

"The security hurt me, broke my shoulder, hurt me too much and me lost feeling," he said.

"[I had] some cut in my leg. I cannot move my leg, I cannot move my neck."

The 31-year-old father of three said he was left in constant pain and suffered debilitating injuries.

"After this I feel very, very tired," he said.

"I feel pain all the time, pain in my shoulders, pain in my kidney and stain in my urine all the time, blood."

Mr Albederee said he has not kept any food down for six months.

"I'm not eating because I can't eat because it makes me pain in my chest," he said.

"This is very, very hard for me. I'm very sad about this because I think I will die."

Albederee 'cut stomach open to prove there was nothing in it'

The Department of Immigration and Border Protection said in a statement that it was providing appropriate medical care for him at the detention centre on Manus Island.

It said it thoroughly investigates allegations of misconduct by contractors, but did not specify if Mr Albederee's case had been investigated or if any action had been taken.

"The Department takes seriously any allegation of misconduct by service provider staff," the statement said.

"These are investigated thoroughly and an appropriate course of action is taken. Detainees have a number of options available to them to report any instances of excessive use of force; this includes the PNG Police."

Mr Albederee said when his condition worsened, he tried to eat again, but was unable to keep anything down.

"Vomiting anything, drink water, vomit, tea, vomit," he said.

"Anything eat, I can't keep anything inside my stomach."

Doctors and asylum seeker advocates have raised Mr Albederee's case with the Department and Immigration Minister Peter Dutton.

Asylum seeker advocate Jeanie Walker said that did not help.

"He became really distressed so he cut his stomach open to prove there was nothing in it."

The Iraqi Embassy in Canberra has also raised the case with the Australian Government.

Staff there fear Mr Albederee will soon die if he is not brought to Australia. Ms Walker agrees.

"I think we're dealing with someone who's very, very strong-willed," she said.

"He shouldn't still be alive but he's also now struggling with fluids, so he's not going to be around for much longer."