Walkers found a 20-year-old man near his vehicle in a gully off Mount Ainslie Drive about 7am on Sunday.

Police believe the crash happened about midnight on Saturday when the man failed to negotiate a bend.

The man, who was the only person in the car, was discovered by walkers the next morning.

He was transported to Canberra Hospital with serious but non-life threatening injuries.

Police have asked for witnesses or people with dash-cam footage of the incident to contact Crime Stoppers on 1800 333 000, quoting reference 6350384.