The Expert will be specific knowledgeable people at the Department of Transport, Arrive Alive Communications, the Road Traffic Management Corporation or others who might have the expertise to answer the question.
Regulation 110 (1) of the National Road Traffic Regulations prescribes the conditions under which a foreign issued driving licence is deemed to be a valid licence. I attach the extract from the Regulations:
(1) Subject to subregulation (3), a driving licence referred to in section 23 (1) (a) of the Act, issued while the holder of it was not permanently or ordinarily resident in the Republic, shall, for the period for, and subject to the conditions under which it was issued, be deemed to be a valid licence for the purposes of Chapter IV of the Act, if—
(a)
(i)
the licence has been issued in an official language of the Republic; or
(ii)
a certificate of authenticity or validity relating to the licence issued in an official language of the Republic by a competent authority, or a translation of that licence in such official language, is attached to it;
(b)
such licence contains or has attached to it, a photograph and the signature of the licence holder.
There is no mention of an expiry date.
Subregulation (3) prescribes that the licence shall only be valid for exchange up to 1 year after the person has obtained or resumed permanent residence. Therefore as long as the licence is valid it may be used to drive and if you obtain or resume permanent residence in South Africa then you have to exchange your driving licence for a SA driving licence within 1 year of this date.