The UNHCR says it is still trying to place 57 refugees held in detention centres in Nauru.
It says hundreds of people continue to be housed in the Australian-run camps, with some of the mainly Middle Eastern detainees having had their applications rejected.
A UNHCR spokesperson, Marissa Bandarangshi, says it cannot be ruled out that some the former boat people may be sent back to countries such as Iraq.
She also says the UNHCR no longer has an office in Nauru but hopes that its appeals will succeed to find new homes for those who have been given refugee status.
"Obviously we would like to see some kind of a resolution to the situation, but what happens to them is ultimately someting to be resolved between Australia and Nauru."