Unionized workers at Hyundai Heavy Industries Co., the world's largest shipbuilder, went on a partial strike Thursday for four hours after pay raise negotiations failed, company officials said.

The 18,000-member union staged a four-hour walkout from 1 p.m., while the negotiations with management have yet to reach a breakthrough. The strike came as a follow-up of its first walkout in 20 years staged last week, when the workers also refused to work for four hours.

Last week, officials claimed only about 3,000 members, or 17 percent, of the union participated in the walkout.

The dispute came as while the company had offered a base salary increase of 37,000 won (US$33.15), stocks equivalent to 100 percent of the base salary and 3 million won in a one-time incentive bonus, unionists are demanding 132,000 won in pay raise, a 6.51 percent hike, and at least 250 percent of the base salary as performance-based benefits. 

Hyundai said while the strike had limited impact on its operations, it will ask the union for compensation as they distracted logistics flow by occupying roads within corporate facilities. 

The union and management have held 58 rounds of negotiations since June through Thursday.

Hyundai Heavy posted a record quarterly operating loss of 1.93 trillion won in the third quarter, with a net loss of 1.46 trillion won. Sales fell 5.6 percent. (Yonhap)