A 12-year-old boy has been arrested over the attempted sexual assault of an elderly woman in Darwin.

Northern Territory Police on Tuesday said the boy allegedly broke into a Coconut Grove house at about 7.30pm on Monday and tried to sexually assault the 76-year-old resident.

Police arrested the boy and the woman was taken to hospital for treatment to a cut on her arm, and has since been released.

Charges are expected to be laid later on Tuesday.

AAP