One person has died and another is seriously injured after two cars collided in south Auckland tonight.

Police said the cars, each with a single occupants, collided head-on at Waiuku near the intersection with Douglas Rd about 8pm.

One person has died at the scene, and another has serious injuries.

Waiuku Rd is closed and traffic is being diverted around the site with cordons in place at Patumahoe and Stuart roads.

The police serious crash unit is investigating.