Tens of thousands of workers at Hyundai Motor Co. and Hyundai Heavy Industries Co. downed tools for the second day of partial strikes on Wednesday, pressing the companies to accept their demands for a pay raise, better working conditions and a halt in tough restructuring moves.

About 15,000 unionized workers at Hyundai Motor, the country's top automaker, walked off the job for four hours from 11:30 a.m. at the company's plant in Ulsan and other facilities. On Tuesday, they also launched a four-hour strike.

Last week, a majority of the automaker's some 48,000 unionized workers voted for a strike as their talks with the company's management over a wage increase and other issues were ruptured.

The workers will also walk out for four hours on both Thursday and Friday. Hyundai Motor estimates there will be some 40 billion won ($35 million) a day in production losses due to the partial strike.

The company's management and labor union will sit together on Thursday to narrow their differences in the wage negotiations.

Meanwhile, unionized workers at its affiliate Kia Motors Corp. are also considering joining the partial strike on Friday, according to industry sources.

Kia's 31,000-member union voted for a strike earlier this month.

Employees at Hyundai Heavy Industries, a major shipyard, launched a partial strike from 1:00 p.m., in Ulsan, a southeastern coastal city.

Hyundai Heavy is one of three local shipbuilders struggling with severe financial strain since the 2008 global economic crisis, which sent new orders tumbling amid a glut of vessels and tougher competition from Chinese rivals.

Also, workers at Samsung Heavy Industries Co. launched their own four-hour strike demanding that the company's restructuring move, which they claim will lead to a cut in workforce, be stopped.

But employees at Daewoo Shipbuilding & Marine Engineering Co., another shipyard, did not join the strike. Instead, they staged a protest at the shipyard during lunchtime.

The country's top three shipyards suffered a combined operating loss of 8.5 trillion won last year due largely to increased costs stemming from a delay in the construction of offshore facilities and an industry-wide slump. Daewoo Shipbuilding alone posted a 5.5 trillion won loss.

The shipbuilders have recently drawn up sweeping self-rescue programs worth 10.35 trillion won in a desperate bid to overcome a protracted slump and mounting losses.

Korea's ruling Saenuri Party urged Hyundai Motor workers to end the latest strike, adding that such actions are hurting numerous subcontractors.

"The average annual wage of Hyundai Motor workers stands at 96 million won," Chung Jin-suk, the floor leader of the party, said.

"Due to (the strike) of such high-income earners, those working at subcontractors that supply parts to Hyundai (and do not get paid as much) are being hurt." (Yonhap)