Fixed term contracts are often used in the labour field for different reasons. Sometimes employees are needed on a project for a specific time period or a position is only available for a time, for instance where an employee is on maternity leave. In the building industry fixed term contracts could be terminated at the arrival of a specific event, for instance a plasterer's contract will terminate if that portion of the project is finalised.
These contracts come to a natural end at the time stipulated in the contract or at the arrival of a specific event, when the employee's services will terminate. That is then the end of the relationship.
From:

http://www.labourguide.co.za/contrac...term-contracts