NSW police sergeant hurt at crash scene

A police officer needed stitches after being struck with broken glass while attending a car accident in Sydney's west.

The officer was on Friday morning responding to reports that a car had been stolen by a woman at Silverwater, who later crashed into a number of cars in Rydalmere.

It's alleged a 17-year-old girl refused to comply with police instructions, and struck the officer with pieces of broken glass as he approached her.

The Sergeant was taken to Westmead Hospital, while the 17-year-old was arrested and taken to Parramatta police station where she is assisting with inquiries.