Police in Blenheim want information on a maroon coloured vehicle involved in a serious crash just south of Blenheim.
A Christchurch man, aged 37, was found lying in the north bound lane of State Highway One, at Welds Pass with serious head injuries, just before midnight on Saturday.
Police believe he had collided with a barrier, but continued driving before pulling over further up the road.
As he got out, his car is believed to have been hit by the maroon vehicle, which left the scene without calling emergency services.
Police say the maroon vehicle was last seen travelling north towards Blenheim at high speed. It has damage to the left side and a broken left headlight.