Emergency services are responding to a head-on crash south of Dunedin.

Police say they were called to the two-car crash at about 9:15 am on SH 1 just south of Waihola.

At least 6 people have been injured. Police say there are serious injuries.

The road is closed, and diversions are in place.

Northbound traffic is being diverted along Phosphate Road, and southbound traffic is being diverted through Taieri Mouth.

Motorists are asked to avoid the area or expect significant delays.

The Serious Crash Unit has been advised.