Reports from Nauru say a six-year-old refugee was allegedly sexually abused.
The Guardian Australia says the perpetrator was caught in the act by her parents, but the man is yet to be arrested or charged.
The girl's father, an Iranian refugee living in Nauru, has hit out at Nauru authorities over what he said was a lack of action, and questioned differing police approaches to crimes involving refugees and locals.
No one has ever been charged for an assault against a refugee or asylum seeker on Nauru, which hosts hundreds of people sent there by Australia.
The organisation hired by Canberra to look after the refugees is bound by Australian legislation not to disclose information related to asylum seekers or the detention centre.