It was previously erroneously reported that children travelling to South Africa from visa-free countries are no longer required to carry their birth certificates. This is not the case.

Children travelling to South Africa – regardless of their country of origin – should always have with them all travel documents including original birth certificate, valid visa if required, and a parental letter of consent where required. We recommend discussing the necessary travel documents with your travel agent/consultant, and confirming with your local consulates before travelling to ensure that you have all the correct documentation for your trip.

Source: http://www.dha.gov.za