Rakaia Bridge down to one lane after crash

The Rakaia Bridge is open but down to one lane this morning after a fatal three-vehicle crash yesterday killed one person and closed State Highway One for more than four hours.

Emergency services were called to the Rakaia Bridge, New Zealand's longest road bridge 30km northeast of Ashburton, about 4.40pm, Ashburton Sergeant Vicki Walker said.

A northbound truck and trailer unit carrying two tractors and a southbound car and ute collided on the bridge.

One person died at the scene and two injured drivers were taken to Ashburton and Christchurch Hospitals, Ms Walker said.

It was unclear what caused the crash but the southbound vehicles were "significantly damaged" and the truck left the carriageway and crashed onto the riverbank three metres below.

The bridge would be partially closed at about 10.30am for further investigations to take place.

The police serious crash unit and commercial vehicle investigation unit were examining the scene.

- NZPA