Amnesty International says urgent medical treatment must be given to a political prisoner, Kimanus Wenda, in Indonesia's Papua region.
It says he has a tumour in his stomach and needs hospital care but the authorities at Nabire prison are refusing to move him.
An Amnesty International spokesperson, Margaret Taylor, says his family and lawyer have requested he be transferred to Jayapura for treatment but the prison authorities have refused.
"One of the reasons they've said they are not transferring him is that they are not prepared to meet the costs of his medical treatment. However they have imprisoned him and we would suggest that imprisonment seems to be after an unfair hearing and needs to be challenged. However he is their responsibility and they must meet their obligations to transfer him to medical care and that's the call we are putting out to the Indonesian government."
Amnesty International says when Wenda was detained eight years ago he was reportedly tortured during interrogation, and soldiers kicked, beat and stamped on him.