Workers at De Beers, the world's leading diamond miner, will down tools in South Africa on Friday over unmet wage demands, the National Union of Mineworkers (NUM) said.
"We're expecting all our members, it's just under 2,000," to take part, said Peter Bailey, the union's chief negotiator.
Three mines and the firm's rough diamond distribution outlet will be affected after a mediation effort failed.
"The strike action will begin with night shift and continue until all wage demands are met," the union said.
The union is pushing for a 13 percent wage increase against the company's six percent. Other grievances include the number of leave days.
Affected operations are Voorspoed mine, Kimberly mine, Venetia mine and the Diamond Trading Company.
The strike is the latest to hit South Africa's mining industry, which has been rocked by wildcat unrest.