Paramedics are on scene and one lane of the highway is blocked, creating traffic problems n the area.

Officers on scene said the man hit a guard rail and came off his bike while travelling at 100km/h.

They said the man, in his late 20s, was thrown from his bike landed about 40 metres away.

He removed his own helmet after the crash and had an "obvious deformity to his left lower leg". When paramedics cut off his jeans, they discovered "a partial amputation" to his lower leg as well as a bad fracture.

Police and fire and rescue also attended the accident, which began about 10.30am.

The man was taken via road ambulance to Albion Park airport, where was airlifted to hospital.