Refugee advocates say witnesses to a fatal attack on an asylum seeker at Australia's Manus Island detention centre in Papua New Guinea are in extreme danger.
Australia's Refugee Action Coalition says asylum seekers raised the alarm on Monday after Wilson Security guards allegedly removed two of their representatives and another asylum seeker, who has since been returned.
The group's spokesperson, Ian Rintoul, says Wilson Security seemed to be responding to routine complaints about the use of the internet and phone.
But Mr Rintoul says the three people were witnesses to an attack on February 17, when asylum seeker Reza Berati was killed and are extremely vulnerable.
"There is no doubt that they have been in danger since the 17th of February and remain in danger. There are very powerful forces in Manus Island that do not want them to give evidence in any court of law about what they have seen."
Ian Rintoul says Australia's Immigration Minister, Scott Morrison, has a duty of care to guarantee asylum seekers' safety.