Twelve people were killed in a collision between two trucks, two cars and a minibus taxi near Ladysmith in northern KwaZulu-Natal on Thursday morning, police said.

Spokesperson Captain Charmaine Struwig said all 12 dead were in the taxi, including the driver. The injured were taken by emergency services to the Ladysmith Provincial Hospital - three were in a critical condition and six others in a serious condition.

The collision took place on the R103 between Ladysmith and the N3 highway.

Struwig said it was believed that a truck had veered into oncoming traffic, colliding with the taxi. Another truck and two cars travelling behind the taxi then crashed into it.

"The taxi was completely ripped open and majority of the passengers were flung out onto the road. The two cars had then [driven over] some of the bodies," she said.

Some of the bodies were found under the truck. Police had launched a search for the driver of the first truck.

"We suspect he ran off because we cannot find him," Struwig said.

It was unknown how many people were in the taxi. Struwig said it was believed to have been coming from the Besters area.

The entire road was closed to traffic.

Police said an accident reconstruction expert from Johannesburg had been called to help with the investigation.

A local journalist at the scene, who spoke on condition of anonymity, said: "It was literally a war zone. We had RTI (Road Traffic Inspectorate) officers throwing up at the side of the road."

Another journalist said: "The taxi was like a Picasso painting, all crushed up." - Sapa