A critical incident investigation is underway after a man was injured in a crash near Singleton at the weekend.
An officer from Traffic and Highway Patrol detected a motorcycle allegedly travelling 145km/h in a 100km/h zone on Putty Road, near Charlton Road, at Bulga - about 20km west of Singleton - about 11.15am on Sunday.
Police said in a statement on Monday morning the officer conducted a u-turn and activated the vehicle's warning lights but he discovered the motorcycle and another vehicle had collided on Bulga Road a short time later.
The rider of the motorcycle - a 71-year-old man - was treated at the scene by NSW Ambulance paramedics for multiple injuries before being airlifted to Royal North Shore Hospital.
A crime scene was established, which was examined by specialist police from the Crash Investigation Unit.
A team from Lake Macquarie Police District has started a critical incident investigation, which will be subject to an independent review.