Police are appealing for witnesses following a fatal four vehicle crash in west Auckland tonight.

One person died and two others were taken to hospital after the collision on the North-Western Motorway about 8.30pm.

Witnesses reported seeing a vehicle travelling the wrong way down the motorway's westbound lanes before the crash occurred.

Auckland serious crash unit Sergeant Stu Kearns said anyone who saw a green four door Mitsubishi Galant travelling in the wrong direction should contact police.

The scene could take several hours to clear and the road was closed between Waterview and Te Atatu, he said.

The serious crash unit is investigating.