Emergency services are responding to a single-vehicle crash on Evans Street in Timaru.
Police were called to the scene of the serious crash about 7.45pm.
Diversions are in place along Beverley Road and Trafalgar Street while the scene is cleared and police said motorists should avoid the area if possible.
The crash is the latest in a string of serious road accidents around the country, with State Highway 63 in the Wairau Valley west of Blenheim closed following a fatal crash earlier this evening and several people injured in crashes in Rotorua, Waikato and Canterbury over the past two days.
Inquiries into the circumstances of the Timaru crash are underway.