Teen in coma after allegedly dragged two km by car

Dean Lewins/AAP PHOTOS

A man is set to face court on dangerous driving charges after a teenager was allegedly dragged two kilometres through streets in Sydney's west before falling from a car.

Police have been told that shortly before 7pm on Friday, a 19-year-old man sitting in a car and a 15-year-old boy began arguing on a street in Blacktown.

It's alleged that as the man drove away, the boy was dragged by the vehicle along two roads before he fell from the vehicle outside a petrol station on Vardys Road in Kings Park.

The 15-year-old was taken to Blacktown Hospital before being transferred to Westmead Children's Hospital and is in a serious but stable condition.

Authorities have confirmed the boy has been placed into an induced coma.

Following inquiries, officers stopped a car in the area near where the boy was found.

The driver was arrested and has been charged with dangerous driving occasioning grievous bodily harm, negligent driving occasioning grievous bodily harm and supplying a prohibited drug.

The Riverstone man was refused bail and appeared at Parramatta Local Court on Saturday morning.

Police are calling for anyone who may have information or dashcam vision to come forward.