The Australian government says a 26-year-old Bangladeshi refugee has died from suspected heart failure in Nauru.
It said the man admitted himself to hospital on Monday complaining of chest pains.
But the Refugee Action Coalition said the truth is the man committed suicide, taking an overdose of pills, possibly Panadol.
The Coalition's Ian Rintoul said the Australian government's claims have angered people in the camps on the island.
He said the dead man's friends say his death was driven by the same desperation affecting others on Nauru.
The Australian government said the man was receiving ongoing treatment in hospital, but died early today after a series of cardiac arrests.
It said an air ambulance was sent but arrived too late.