A foreigner who falls within a certain professional criteria in which skills (which is determined by the South African Quota Work List) are considered scarce within South Africa qualify for Quota Work permit. 

No employer is required for this permit to be issued by the Department of Home Affairs.  This work permit requires the inclusion of confirmation that the foreigner who is applying for this permit possesses the necessary qualifications, certified and approved by the South Africa Qualifications Authority (SAQA) and confirmation that the applicant has at least 5 years of relevant working experience in the appropriate specified field amongst other documentation. 

If a foreigner enters South Africa on a Quota work permit, the holder must submit confirmation of having secured employment within a specific category within 90 days after arrival (i.e. the Quota Work List issued by the Department of Home Affairs).

For further information on South African Quota work permits, please see here

Information supplied by www.intergate-immigration.com