About 6pm a number of family and friends had been trail bike riding through the Mullion Range State Forest, Long Point Road in Mullion Creek, about 18 kilometres north of Orange.

A 43-year-old man was completing a ride on a trail bike with a 13-year-old female pillion passenger when it's believed the bike left the dirt trail, veering into vegetation and causing the pair to fall from the bike.

Two nearby riders assisted at the scene and drove the man to a nearby road, where emergency services were called.

Ambulance paramedics assisted the man; however he died at the scene.

The girl suffered minor injuries. No one else was injured during the incident.

Officers attached to Canobolas Local Area Command attended and commenced investigations.

It's believed the man was not wearing a helmet or protective clothing; however the girl was at the time of the incident.

Police will prepare a report for the information of the coroner.