Western Cape Traffic Department Chief Kenney Africa said nine people had been occupants of the Ford Sierra when the accident took place around 13:00.
Initial investigations showed that the driver had lost control of the vehicle, it then overturned before bursting into flames.
Five adults and two children were burnt beyond recognition, Africa said.
Two other occupants, a man and a 5-year-old boy were seriously injured and taken to a nearby hospital for further treatment.
Africa said the car had been overloaded.
- Mpho Raborife, News24