At approximately 4:20pm yesterday,  a 57-year-old woman from Gravelly Beach has had a medical episode while driving her black Holden Barina sedan on the West Tamar Highway at Trevallyn.

The woman who was travelling in the north bound traffic lanes has run into two unoccupied parked vehicles before coming to a stop. Members of the public rendered assistance before ambulance personnel and the Tasmania Fire Service attended.

The woman was extracted from the vehicle and taken to the Launceston General Hospital. A short time later the woman was taken by air ambulance to the Royal Hobart Hospital in a serious condition.

No one else was injured as a result of the crash.

Police are investigating the crash and are asking any members of the public who have dash cam footage or who witnessed the incident to come forward.