A woman in her 50s remains in hospital with serious head injuries after being hit by a vehicle in western Sydney this morning.

CareFlight’s rapid response rescue helicopter was called to Pendle Hill before 9am, landing in the grounds of heritage site Dunmore House.

It is understood the local woman had been walking with a friend when she was struck by a vehicle.

CareFlight’s specialist doctor and intensive care paramedic treated the injured woman at the scene, intubating and stabilising her.

The medical crew then accompanied the patient, together with NSW Ambulance paramedics, by road to Westmead Hospital. She arrived in a serious condition.