Seven people died when three vehicles collided and burst into flames on the R34 at Gluckstad between Melmoth and Vryheid in northern KwaZulu-Natal yesterday.
Four people survived the horrific crash and two are reported to be in a critical condition in hospital. Two others sustained serious injuries.
Initial police reports indicate the accident happened when three vehicles - a Tata, Toyota and Colt bakkie - collided.
Traffic officers will reconstruct the accident scene to establish the cause. Police are investigating seven counts of culpable homicide.
In another accident at the weekend, three women and a man were killed and three other people were seriously injured in an accident involving two cars at Westville in Durban.
Emergency workers used the jaws of life to remove two of the seriously injured victims. Initial reports indicate speed was a factor in the crash.
In a separate incident on Sunday, seven fishermen were severely injured when the 4x4 they were travelling in crashed into a bridge at Umgababa in KwaZulu-Natal.
KwaZulu-Natal MEC for transport, community and liaison, Bheki Cele said police would reconstruct this accident as well "to determine the cause of such a gruesome accident".
"Furthermore our road safety officials will gather all relevant information," he said.