Johannesburg - Four people were killed when the bus they were travelling in went down an embankment on the M25 near KwaMashu in KwaZulu-Natal on Tuesday, said paramedics.
Three people sustained critical injuries in the accident, said KZN Emergency Medical Services spokesperson Robert Mckenzie.
They were airlifted to hospital.
"The other 25 patients who sustained serious as well as minor injuries have been transported to King Edward, Addington and Mahatma Gandhi hospitals for continued care," said Mckenzie.
The cause of the accident was not immediately clear.