Emergency services responded to reports of a singe-vehicle accident on the Gwydir Highway, east of Inverell, just before 11.30am on Saturday.
Initial reports found a female, believed to be the sole occupant of the vehicle, ejected during the collision and in need of immediate assistance.
Local paramedics commenced treatment of the 45-year-old for multiple traumatic injuries. Ambulance New South Wales tasked the Westpac Rescue Helicopter Service to transport the female.
The helicopter's critical care medical team assisted with treatment and stabilisation of the patient before being flown direct to The Tamworth Rural Referral Hospital in a serious but stable condition.
Further investigations found the single vehicle had run off the road and collided with a tree.