In order to work in South Africa one will need to qualify for a work permit. In most circumstances the individual will require a job offer first and comply with a range of associated requirements such as your employer needing to show that they first made a reasonable attempt to consider a South African applicant, have your qualifications assessed and evaluated etc. There are permits that accommodate highly or exceptionally skilled applicants upon confirming that the skills and qualifications are limited and of benefit to South Africa but these permits are soon going to be removed from the Immigration Act therefore no detailed in this guide.
As work permits in South Africa are issued to a person based on that person meeting specific requirements for the particular job that was offered, the person will need to apply for a new work permit and meet the requirements again to be able to work for a new employer.
The validity of permits can vary depending on what type of permit is applied for. It is generally up to the discretion of the Department of Home Affairs.
A work permit can be issued up to 5 years, Intra- company transfer work permits can only be issued up to 2 years etc.
- The above information is from the http://www.immigrationsouthafrica.org -