Officers from Hunter Valley Police District investigating circumstances of fatal collision on Wybong Road, Castle Rock

AN investigation is underway into a fatal collision involving a motorcycle and a car near Muswellbrook on Saturday afternoon.

Emergency services responded following reports a Harley Davidson motorcycle and a silver Holden Commodore collided on Wybong Road, Castle Rock, just after 2.30pm on September 7.

The 47-year-old male motorcyclist died at the scene.

The five occupants of the vehicle, which included a three-year-old child, were treated by NSW Ambulance paramedics before being taken to hospital for treatment to non-life-threatening injuries.

Wybong Road was closed in both directions for a number of hours while specialist forensic officers examined the scene.

Officers from Hunter Valley Police District are now investigating the circumstances surrounding the crash.

Anyone with information that may assist them is urged to contact Crime Stoppers on 1800 333 000 or https://nsw.crimestoppers.com.au