There were "multiple people injured", at least one critically, after three buses collided on the N2 near Gingindlovu, north of Durban, on Sunday.
First responders at the scene, who spoke to News24 on condition of anonymity, said the buses were packed with IFP supporters, on their way to attend the party's manifesto launch in the city.
Pictures show wrecked coaches at the roadside and another smashed into a tree. People in party regalia can be seen lying near the road.
IPSS Medical Rescue spokesperson Samantha Meyrick said medics had responded to the scene and found scores of wounded.
"Three buses collided, leaving many of the passengers injured and others trapped in the wreckage. Firefighters worked to extricate the trapped while paramedics started the treatment," she said.
She added that eight people were badly wounded, among them one person who was in a critical condition.
Meyrick said that the total casualty count could not yet be confirmed, and state emergency personnel had deployed a mass casualty bus to the scene.