Labor unionists of South Korea's biggest umbrella union said Thursday that an estimated 130,000 members will stage a second nationwide strike to demand better working conditions.

Affiliated companies of the Korean Metal Workers' Union (KMWU), one of the largest industrial guilds under the progressive Korean Confederation of Trade Unions (KCTU), will go on a one-day walkout on Friday, following the last one a week ago, said the KMWU.

The member companies include the nation's top automakers -- Hyundai Motor Co., Kia Motors Corp., and GM Korea Co. Strikes at Hyundai Motor and Kia Motors were the first work stoppages in four years.

The KMWU said the strike is aimed at scrapping the nighttime work system, rooting out unfair transactions between companies and subcontractors, abolishing the temporary workers system and improving labor conditions.

It noted that it will hold the second round of the general walkout on Friday because its demands were not met after the first work stoppage.

A total of 128,000 workers participated in the previous walkout, according to the KMWU.

(Yonhap News)