About 93 percent of a total of 6,503 workers voted in favor of a strike, the labor union said. The timing and extent of the strike will depend on the progress of the sale, it added.
The decision came after the state-run Korea Development Bank and other creditors announced earlier this month that they plan to select a preferred bidder as early as August to sell their combined 50.4 percent stake in the shipyard, South Korea's Yonhap News Agency said.
The 50.4 percent stake in Daewoo Shipbuilding was valued at about 4.2 billion U.S. dollars at current market prices.