Boy, 5, hit by car in Sydney driveway

A five-year-old boy has been taken to hospital after he was hit by a car driven by his mother in the driveway of their home in Sydney's northwest.

The 41-year-old mother struck her son just before 5pm on Thursday then started taking him to hospital before pulling over at Castle Hill upon advice from NSW Ambulance paramedics, police say.

The boy was treated at the scene and taken to Westmead Children's Hospital.