Three men and a woman were killed when a truck was ripped open when it crashed into a tree near Nelspruit on Saturday morning, paramedics said.
ER24 spokesperson Werner Vermaak said all four occupants of the truck were flung out of the vehicle when it hit the tree.
The truck was broken up completely when paramedics arrived at the scene on the N4 near Schagen.
"Sadly, there was nothing that could be done for them and they were declared dead on the scene."
Authorities will investigate the circumstances of the crash.