Tens of thousands of unionized workers of Hyundai Motor Co. and Kia Motors Corp. have voted in favor of striking, officials said Wednesday, setting the stage for a costly walkout after just one year since their last strike that cut into the carmakers' vehicle output.

Still, the unions are not allowed to down tools immediately as they were to meet with managements later in the day as part of the mandatory mediation by a state-run labor body.

By law, a union cannot go on strike during mediation by the National Labor Relations Commission, which usually lasts 10 days.

The commission said its mediation is set to end on Aug. 19 when it can ask the labor and management to either hold more negotiations or halt its mediation, meaning the workers could walk off the job anytime starting Aug. 20.

Kwon Oh-il, a spokesman for the Hyundai union, said the union's authorization to strike is an expression of outrage by the union toward the company, though he said the union can sit down for talks with the management if the company offers acceptable deals.

"Our goal is not a strike," he said, adding that "the company should offer positive proposals if it does not want a disruption" of assembly plants in the country.

His comments came after the union members' votes were counted.

Of the 40,537 who voted out of the total 46,027 members of the union, some 80.4 percent, or 32,591, voted in favor of striking.

The carmaker called for a quick resumption of in-depth negotiations to conclude a wage deal.

Last week, the unions of Hyundai and its sister company Kia declared that their negotiations with the managements collapsed and called on the labor commission to intervene.

Last year, Hyundai's unionized workers staged a 13-day partial strike, preventing the carmaker from producing 82,000 vehicles and costing it 1.7 trillion won (US$1.5 billion) in lost production.

Hyundai runs three assembly plants in South Korea and several others in China, the United States, India, Turkey, the Czech Republic, Brazil and Russia. Last year, Hyundai produced 1.91 million vehicles in South Korea, compared with 2.5 million units built at its overseas plants.

Separately, more than 21,500 out of 30,486 Kia union members also voted in favor of a strike.

Kia union said it had no immediate comment on the looming work stoppage.

Last year, Kia could not produce 62,000 vehicles during a 12-day partial strike of its union, costing it 1.03 trillion won in lost production.

Strikes have plagued Hyundai Motor for decades. The unionized workers have downed tools every year due to wage disputes since 1986, except in 2007, 2009, 2010 and 2011, according to the carmaker.

Kia's union went 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.

Separately, Hyundai confirmed it was recalling 239,000 Sonata and Azera sedans in the U.S. due to a problem with their rear suspension that can be corroded by road salt, according to a media report by the Associated Press. (Yonhap News)