A collision between at least two vehicles near Maclean was the end result of a high speed pursuit on the Pacific Highway a few minutes ago.
Police arrested one man allegedly involved in the pursuit and early indications were that there were children in the car.
At 1.45pm police were tracking the car near the Iluka turnoff at speeds of more than 180kmh.
Trucks were said to be blocking the driver's path at the time.
Injuries to the occupants of a second car involved in the collision have been reported but not confirmed.
Updates to follow.