NSW boy hit by car while riding scooter

A boy is in a serious condition after his leg was trapped under a 4WD outside a childcare centre in Sydney's west.

The 11-year-old is believed to have been riding his scooter across the driveway of the centre in Penrith when he was hit on Friday afternoon.

Witness Rick Edington said he heard the boy's screams from his nearby business.

"The actual wheel was sitting on top of his leg and it was all twisted - it was really terrible," he told Channel Nine.

The boy was taken to The Children's Hospital at Westmead and remains in a serious but stable condition.