Northern Territory Police Force have arrested a 37-year-old male in relation to a sexual assault committed on a female, aged under 16, in the Palmerston CBD late yesterday afternoon.

The offender was not known to the victim.

Detectives from the Child Abuse Taskforce identified and arrested the alleged offender earlier today.

He remains in police custody, with charges expected to be laid later this evening.

Anyone who witnesses crime is urged to contact police on 131 444 or dial Triple Zero in an emergency. You can anonymously report crime via Crime Stoppers on 1800 333 000.