Update 12:20pm: The woman is in a critical condition with serious head injuries, upper arm injuries and suspected pelvic injuries.
She is being transported by Careflight helicopter to Westmead Hospital.
Four paramedic units and the Careflight medical team attended the scene and have provided the woman with advanced medical care.
Careflight is on its way to attend an accident involving a motorcyclist on the Great Western Highway near Charles Street at Lawson on Thursday morning.
According to Live Traffic at 11.30am, there are heavy traffic conditions with one lane of the highway closed in each direction.
A NSW Ambulance spokesman said a 54-year-old woman is being treated on scene by paramedics and the Careflight medical team for a head injury and potential neck, back and leg injuries.
He said paramedics received a call out around 10.35am to reports of an accident involving a car and a motorcycle.
Blue Mountains Police and other emergency services are currently on scene.
Police have asked motorists to reduce their speed if travelling through the accident site.
