A refugee advocate says health problems among the men stuck on Manus Island are coming to a head as the humanitarian crisis there deepens.
Around 400 refugees are holed up in Australia's decommissioned detention centre on the Papua New Guinea island.
They're refusing to adhere to calls by PNG officials for them to move to alternative accommodation in Manus' Lorengau town.
These men have now lacked access to clean water for 20 days, while an effective blockade on their access to health services and food remains in place.
Ian Rintoul of the Refugee Action Coalition said medicine shortages were beginning to bite.
"Prescription drugs that people were getting day by day, well that's finished, that's starting to become more acute. So the medicine side of things, is the thing that's hitting very hard at the moment, but that's not to under-estimate at all the difficulties of trying to exist without power, water and food."
Mr Rintoul said that contrary to Australian and PNG government claims, the alternative accommodation facilities in Lorengau were not all ready to take the refugees.
He said that two of the three Lorengau facilities, Hillside Haus and West Lorengau, were clearly not adequate for the small number of refugees who had moved over.
"The administration of the place is not ready. So people haven't been able to get food, they haven't been able to get medicine, because the arrangements for those things are still not in place."