Detaining of refugees 'inhumane': UN Australia has been accused of almost 150 violations of international law by a United Nations committee for its "inhumane" indefinite detention of 46 refugees. The United Nations Human Rights Committee has called for the mainly Tamil refugees to be freed and labelled their detention "cruel, inhumane and degrading." The complaint was lodged three years ago by Professor Ben Saul from the University of Sydney's Centre for International Law. He says the findings are embarrassing and will damage Australia's international reputation. "We frequently criticise the human rights performance of other countries and yet we don't have our house in order," Professor Saul told AAP on Thursday. The detainees were given refugee status, but were deemed a security threat and held in detention for at least two and a half years. They say they've been unable to challenge the legality of their detention in Australian courts. Australia has 180 days to respond to the findings. The federal government told the committee releasing classified details would compromise the assessment system and national security. However it did explain the refugees posed one or more of three specific risks. Prof Saul is hopeful the findings will be enough to shift the government's position on indefinite detention. "I think now it's really beyond doubt that these are very serious and numerous violations of international law," he said. Amnesty International said Australia's policy of indefinite detention of refugees had become "an international embarrassment" and a stain on its legal system. Meanwhile, the immigration department on Thursday released a three-minute subtitled video of asylum seekers on Papua New Guinea's Manus Island warning others not to take boat journeys to Australia. Their faces are blurred out but their voices are clear as they describe their ordeals. "Please, I'm asking people, it's a big mistake, please don't take this journey," one man says. Another man describes how people smugglers promised him $10,000 on arrival in Australia. He said they took him and other refugees to a small hut in a jungle. There they were locked up with no proper food or water, and had to go to the toilet in plastic bags. Immigration Minister Tony Burke said the men interviewed were offered no incentive and were not prompted or told what to say. Australian Greens senator Sarah Hanson-Young described the video as "hostage-style."