Unionized workers at South Korea's largest carmaker Hyundai Motor Co. vowed to stage partial strikes again after they failed to narrow differences with the management over the latest dispute over wages, union officials said Friday.

Union spokesman Kwon Oh-il said the 46,000-strong labor union will put down tools for eight hours each on Friday and Monday to press its demand for higher wages and more fringe benefits.

"The management's proposals fell short of our union's expectations," Kwon said by phone from Ulsan, home to Hyundai's main production facility, located some 410 kilometers southeast of Seoul. He did not elaborate on the management's proposals.

Still, Kwon said his union will sit down for talks with the management on Tuesday for a second round of negotiations.

The management called on union leaders to negotiate their way out of the dispute.

"The union needs to show a mature attitude by focusing on negotiations rather than strikes that bring harm to both the union and the management if the union truly wants to resolve the issue," said a company official involved in the labor issue.

Hyundai's union is demanding, among other things, a hike of 130,498 won (US$117) in basic salaries and a one-year extension of the retirement age to 61, as well as a performance-based bonus equal to 30 percent of the company's net profit last year, which reached 9 trillion won.

It also called for 10 million won each for workers' children who choose to seek employment instead of going to college.

The negotiations came a day after Hyundai Motor Chairman Chung Mong-koo met with Gov. Nathan Deal of Georgia in Seoul ahead of Deal's trip to China and Japan between Thursday and next Friday.

Hyundai officials declined to elaborate on the meeting. Still, the rare meeting raised speculation that Deal may have asked Chung to expand Kia Motors' assembly plant in Georgia, which currently has the annual production capacity of 360,000 units.

Kia is Hyundai's smaller sister company, and the two together form the world's fifth-largest carmaker.

Hyundai has a separate assembly plant in Montgomery, Alabama, which has an annual production capacity of 360,000 units.

Repeated calls to Deal's office seeking comment went unanswered late Thursday. An email seeking comment from Deal was also not immediately returned.

In May, Chung said that he had no immediate plans to expand factories in the United States, though his group has been struggling with a short supply in the second-largest market due to strikes at home.

Also Thursday, about 30,000 unionized workers of Kia, Hyundai's smaller sister company, returned to their jobs, a day after staging a partial strike to bolster their demands for higher wages and other fringe benefits, according to a Kia official.

Still, the Kia official said his company has no plans to hold full-scale negotiations with the union this week, though working-level contacts are still under way. A Kia union official handling the media was not immediately reached for comment.

The partial strikes earlier this week prevented Hyundai and Kia from producing 5,447 units, costing the carmakers 108 billion won in lost production, according to company officials.

Labor disputes at Hyundai Motor have been an almost annual event in the past two decades. Its workers have downed their tools every year since 1986 except for in 1994, 2009, 2010 and 2011. A strike last year cost the carmaker some 1.7 trillion won in lost production.

Kia's union has gone on strike every year except in 2010 and 2011 since 1999, when the country's No. 2 carmaker was taken over by Hyundai following the 1997-98 Asian financial crisis.

(Yonhap News)