The union said 56.1 percent of 8,804 union members who cast ballots voted against the agreement signed by the company and the union in December. More than 1,000 union members did not participate in the vote held earlier in the day at the shipyard in Ulsan, an industrial city located about 410 kilometers southeast of Seoul.
The union said discontent over performance-related bonuses may be to blame for the wage deal being rejected by workers.
A Hyundai Heavy official said the company did not have an immediate comment on the result.
It remains unclear when the two sides will sit down again for wage negotiations.
Last week, Hyundai Heavy President and CEO Kang Hwan-goo warned of an unprecedented crisis due to declining order backlogs.
The shipbuilder said it aims to achieve 7.98 trillion won (US$7.5 billion) in sales this year, a 60 percent decline from a decade ago. (Yonhap)