The message comes in the form of a letter written by an asylum seeker at the Australian-run facility in Papua New Guinea and obtained by the ABC after six days of protests.
“All asylum seekers on Manus Island in hunger strike ask you to hand over our medical records to organ donation organisation in case of our fatalities inside the cage,” said the letter, addressed to service providers Transfield and International Health and Medical Service.
“This way at least a part of us may one day feel sweet taste of FREEDOM.”
Photographs and footage have been sent to the media by asylum seekers showing men being carried away on stretchers who have reportedly fainted after days of hunger striking.
In one video, a man is lifted into what appears to be a dormitory at the centre.
On the back of the door graffiti reads: “The Aussie Nigga.”
The asylum seeker who sent the footage said he did not know which compound it was from or what it meant.
Racial slurs against Papua New Guineans were a factor in the riots that claimed the life of Reza Barati almost a year ago.
Separate photographs of graffiti written on doors read “Help us!!” and “here is the humanity?” and “They killed our soul!!!”.
Banners hung at the centre asked for assistance from the United Nations and Red Cross.
The asylum seekers are protesting about the prospect of refugees being resettled in PNG.
Asylum seekers have barricaded Delta compound and are not allowing staff to enter. It usually accommodates more than 200 men.
Other compounds remain open but asylum seekers are engaging in protest activities, with the situation at Oscar compound reportedly becoming volatile on Sunday evening.
An asylum seeker told the ABC two people drank mosquito repellent and another two drank detergent as part of their protest on Saturday night.
He said others were threatening suicide.
The Australian and PNG governments have said “non-compliant behaviour” would not change the outcomes for those seeking asylum, with resettlement in PNG the only option.
Asylum seekers said earlier they were being denied food and water and had sent photos of men burrowing beneath a fence to reach crates of bottled water placed just outside the compound.
A spokesman for Immigration Minister Peter Dutton said the Government had been "advised that food and water continue to be available".
“However, normal services and supplies in certain areas of the centre have been affected by the disruptive behaviour of some transferees. Normal services are ready to resume in those areas as soon as the situation allows,” the spokesman said.