Korea's largest umbrella union said Tuesday that it has called for a nationwide strike to push for an end to irregular workers and the revision of existing labor laws.

The walkouts are expected to affect 137,000 workers and marks the first time in four years that the Korean Confederation of Trade Unions has called for a general strike.

The umbrella union added that it has called for 20,000 workers from all over the country to converge in Seoul on Friday to take part in a protest rally and make known their demands.

The KCTU said besides calling for an end to irregular workers and changes to labor-related laws, it wants the government to stop businesses from laying off workers because of difficult conditions.

They have also said they want Seoul to halt privatization of public companies.

Related to the call for strike, unionists at Hyundai Motor Co., South Korea's No. 1 carmaker, said members will stop work for six hours, with the country's construction workers unions to not report to work for one day.

Other industries are expected to disrupt work by calling for meetings of unionists, although the medical workers said they would delay staging a strike for a week.

Despite the decision to move ahead with the strike, the total number of participants is smaller than what the KCTU had predicted in June. (Yonhap News)