A male has been flown by helicopter to Wellington Hospital in a critical condition following a two car crash on State Highway 6 between Havelock and Renwick in Marlborough.
An ambulance, a response vehicle and the Nelson rescue helicopter attended the scene on SH6 between Okaramio and Havelock after being alerted to the incident at 3.54pm. Police and the Fire Service also attended the crash.
Two others, also involved in the incident, sustained minor injuries and were not been taken to hospital.
One lane on SH6 between Okaramio and Havelock is now open but police have warned motorists to still expect delays.
Traffic travelling between Blenheim and Nelson will need to go via Queen Charlotte Drive and Picton, or via the Wairau Valley.