Twenty people were confirmed dead by 9am on Saturday after the bus they were travelling in overturned and plunged into a river near Wepener, Free State police said.
Captain Elsa Gerber said 77 other passengers were removed from the wreckage and transported to several hospitals in the province.
The bus was travelling from Secunda in Mpumalanga to Idutywa in the Eastern Cape.
Police divers are still searching the river downstream to check for more survivors or bodies. – Sapa