Just after 8pm on Saturday, December 31, a teenage boy was driving a Holden Colorado utility along Leonard Road, Hanwood with a teen passenger, both aged 17.

The vehicle stopped outside the front of a home on the same street. Police have been told that a third teenage boy approached the vehicle and stood on the side step of the car, when the car took off, causing the boy to fall from the utility.

He was treated at the scene by NSW Ambulance Paramedics before being taken to Griffith Hospital with head injuries.

The boy was placed in an induced coma and airlifted to St George Hospital; his condition remains as stable.

The driver was also treated at the scene for shock, before being taken to hospital for mandatory blood and urine tests.

Officers from the Griffith Local Area Command established a crime scene and commenced an investigation and inquiries are continuing.

Police are urging anyone with information in relation to this incident to call Crime Stoppers on 1800 333 000 or Griffith Police on 6969 4299.