Sydney boy aged four hit by car, dies

A young boy who was run over by a car in Sydney's west has died in hospital.

The four-year-old was crossing a residential road in Westmead on Tuesday afternoon with his mother and brother when he was hit, leaving him with serious head injuries, police said.

Paramedics tried to revive the child at the scene before taking him to Westmead Hospital, where he later died.

"The child's mother sustained minor injuries in the collision and was also taken to Westmead Hospital for treatment. The other child was not injured," police said.

The woman driver wasn't hurt and has been taken for mandatory blood and urine tests.