Johannesburg - Cosatu announced that more than 4 000 staffers of Sun International decided to go on strike on Friday to demand higher pay.
Cosatu said on Thursday the workers from 16 Sun International hotels and casinos would also stage a "march and handover a memorandum with their demands to management."
The decision to down tools follows a collapse of wage negotiations between unions and the hotel chain. The government labour arbitrator has failed to resolve the dispute.
Simphiwe Nikiwe, a negotiator with a Cosatu affiliate union, said that workers were demanding a 10% pay rise to be back-dated to July, but their employer had offered only 6.5%.
Among the hotels to be affected are Sun City, the Grand West Casino and Entertainment World in Cape Town.