Reports from Australia say asylum-seekers at its detention centre in Papua New Guinea have been warned that PNG police could move in to end their protest.
The Refugee Action Coalition says hundreds of asylum seekers are on hunger strike and refusing to return to their compounds in a protest triggered by a water supply problem.
However, Australian authorities say it is incorrect to say the asylum seekers at the Manus centre were involved in food and fluid refusal.
A Coalition spokesman says the threat of police action has added to the fears and tension at the camp.
Tensions have been rising in recent days as most of the asylum seekers approach 18 months of detention on Manus Island and at least one protester has stitched his lips shut.
The camp has also seen riots, which resulted in the killing of an Iranian asylum seeker last year.