Johannesburg - Wage talks with the world's largest diamond producer De Beers will get under way on Wednesday, the National Union of Mineworkers (Num) said.
It would be held with a facilitator from the Commission for Conciliation, Mediation and Arbitration (CCMA), spokesperson Lesiba Seshoka said in a statement.
The diamond giant has offered a 5% wage increase but the union wants 10% more.
"The Num remains optimistic for a peaceful resolution," he said.
"We hope that De Beers will understand that we really mean business when we argue for 15%."
Seshoka said it was not their intention to strike but if "pushed", it would resort to that.
De Beers industrial relations head Wayne Smerdon was not immediately available for comment.