About 400 refugees are still refusing to leave the former detention centre on the Papua New Guinea island after it was closed at the end of October when essential services were cut.
The deputy regional representative of the UN refugee agency (UNHCR), Nai Jit Lam, said Australia remained responsible for the refugees and should engage them in constructive dialogue.
"This is a man-made and entirely preventable humanitarian crisis. It is a damning indictment of a policy meant to avoid Australia's international obligations," the UNHCR added.
