An investigation is underway following a crash at Seven Hills this afternoon, NSW Police say.
About 4.30pm today, police from Blacktown Traffic and Highway Patrol attempted to stop a trail bike on Leabons Lane.
The rider, a 15-year-old boy, allegedly failed to stop and a short time later crashed into a grey Lexus sedan.
The rider was treated at the scene by NSW Ambulance Paramedics before being taken to the Children's Hospital at Westmead with serious injuries.
The driver of the Lexus was not injured, and has been taken to hospital for mandatory blood and urine analysis.
Leabons Lane is currently closed as investigations take place.
Police are urging anyone with information in relation to this incident to call Crime Stopers.