Arms company Denel Dynamics has been ordered to permanently appoint a woman worker after 24 months of service as a contract worker, trade union Solidarity said on Thursday.

Spokesman Dirk Groenewald said the Labour Court in Johannesburg made the order on Wednesday.

"Denel Dynamics' conditions of service clearly state that employees appointed on a contractual basis for more than 24 months should, after this period, be appointed permanently."

The woman, Ansie van Niekerk, met all the requirements for the position, but was not appointed because she was white, he said.

Groenewald said Van Niekerk's fixed-term contract as a senior secretary was renewed seven times, from February 2009 to February 2011. In the period she applied for a permanent position three times.

An external candidate, a black woman, was given the job, although the company's policy states that preference must be given to internal candidates.

"Judge André van Niekerk ordered Denel Dynamics to adhere to its conditions of service concerning temporary hourly employees," Groenewald said.

"[It has] to appoint Van Niekerk retroactively as a senior secretary, or in a similar position. Denel Dynamics was also ordered to pay the costs of the proceedings."

Groenewald said white employees were often appointed on a contractual basis while companies waited for affirmative action candidates to apply. This amounted to unfair discrimination and white employees ultimately had to be appointed permanently, as in this case, he said.