The union said 40,000 workers at Hyundai Motor Company would take part.

"We will start with a four-hour strike tomorrow [Wednesday] as scheduled," said a union spokesman.

The decision to strike followed a call by the Korean Confederation of Trade Unions (KCTU) for a nationwide walkout on Wednesday.

Analysts have attributed spreading labour unrest in South Korea to the failure of President Roh Moo-hyun's government to take tough action on labour issues.

A recent strike at Chohung Bank was widely seen as a success for unions as it resulted in higher wages and jobs being guaranteed for three years.

Business groups have reacted angrily to the industrial action, threatening to cut investment or shift factories abroad unless the government reins in unions.

'Excessive demands'

Hyundai unions and management have been in talks for two months over wages and working conditions.

Unions want an average 11% wage rise and a four-hour reduction to 40 hours in the working week.

A Hyundai spokesman said the union had also demanded the right to take part in company decision-making.

"They are making excessive demands," he said.

The KCTU said 100,000 workers at 100 workplaces across South Korea would participate in Wednesday's industrial action.