It took emergency crews about an hour to free a woman from her car following a head-on crash in Werrington on Thursday night.
The woman, 27, was rushed to Westmead Hospital in a critical condition with serious leg injuries after the collision on Dunheved Road, Werrington.
Her passenger, a 16-year-old boy, was also taken to Westmead Hospital with non-life threatening injuries. Both are from Penrith.
Six people were injured in the incident.
Police said a Holden Commodore utility and a Holden Commodore sedan, which had crossed onto the wrong side of the road, collided head-on about 7.35pm.
The driver of the sedan, a 14-year-old boy from Bidwill, sustained serious abdominal injuries and fractures in the crash.
He was taken to The Children’s Hospital at Westmead, as were two passengers, 14 and 16, from Blackett and Hassall Grove respectively.
They sustained minor injuries.
A fourth passenger, 18, from Mount Druitt, who was sitting in the back seat, was also taken to Westmead Hospital for treatment to leg injuries.
Detective Inspector Katie Orr said the woman and boy travelling in the utility were “at the wrong place at the wrong time”.
She said the passengers in the sedan had not yet spoken with police.
Police attached to the Metropolitan Crash Unit have conducted a forensic examination of the scene.
Detective Inspector Orr said police were seeking dashcam to assist with their investigation.
Anyone with information about the incident should call Crime Stoppers, 1800 333 000, or use the online reporting tool.