Fears have been voiced over the health of five inmates - all believed to be asylum seekers - who are on a hunger strike at Hong Kong's biggest immigration detention centre. Some of the men at the Castle Peak Bay Immigration Centre in Tuen Mun had been refusing food for more than a month, said another detainee, who was not taking part. The United Nation's refugee agency in Hong Kong confirmed last night that at least three of the men were asylum seekers who had been in the city for up to two years. The detainee said a fourth asylum seeker and a man whose claim for asylum was rejected were also on the hunger strike. The protest began 34 days ago, and three of the 'very thin' protesters are from India and two from Pakistan. 'They cannot walk, they cannot move. When I see them they cannot open their eyes. They have no energy to talk,' said the inmate, who last saw the men on Tuesday. It is understood the men have been refusing meals since August 20. The detainee said the men stopped eating after they were beaten, but the Immigration Department would not confirm the allegation. The department said the men were refusing meals, but were getting 'supplementary food such as milk tea and bread on request'. Four of the five are in the centre's medical bay. The department said their requests for release from the centre would be considered. The facility, opened in 2005, can accommodate up to 400 inmates. The department took over management from Correctional Services last year. Inmates may have overstayed their visas, entered Hong Kong illegally or used false identity documents, but they have not been tried as criminals. People who wish to seek asylum in Hong Kong must overstay their visas, exposing themselves to arrest, before the government allows them to make a claim for protection. Barnes & Daly, a law firm that specialises in human rights, recently challenged that policy in the Court of Appeal. It said hunger strikes were a historical way for those detained arbitrarily for weeks to get attention. 'They have no clue why they're there. It's like a never-ending, seemingly indefinite, detention,' Patsy Ho, a solicitor at the firm, said. 'As far as they know, the more they strike, the earlier they can get an answer to their questions. It's one of the only ways they know they can see an immigration officer.' The strike echoes a string of similar protests between 2006 and 2008, though the alleged 34 days in this case is uncommon. People usually die after 60 days without food.