16 asylum seekers on Nauru have appeared in court, accused of causing 24,000 US dollars in damage at a riot at the processing centre in September.
They have been charged with rioting injuring buildings and wilful damage.
A Nauru government spokesman has told the newspaper, The Age, that additional charges of common assault were levelled against four men.
All are being tried under Nauruan law, and the charges carry possible jail terms of up to seven years.
Two of the group have voluntarily returned to Iran since the incident.