Sydney man run down by car, unconscious

A man is unconscious in hospital after being rammed by a car and assaulted in Sydney's west.

Police say they've been told the victim, believed aged in his 50s, was run over by a car and attacked in Shalvey about 2pm on Saturday.

He remains in Westmead Hospital in a serious condition while a 40-year-old man, believed to be known to him, was arrested at the scene and taken to Mount Druitt Hospital for mandatory blood and urine tests.