Prime Mister Hwang Kyo-ahn on Tuesday vowed to take stern measures against a walkout by a major labor organization.

The warning comes as the Korea Confederation of Trade Unions (KCTU), one of the country's two umbrella labor groups, was to go on an indefinite walkout in protest of the government's adoption of contentious labor guidelines.

"The KCTU's general strike is a clear illicit strike that goes against a difficult economic situation both home and abroad, crisis such as North Korea's nuclear test, and the hopes of young job seekers," Hwang said during a Cabinet meeting.

Last week, the Ministry of Labor and Employment announced that it will ease restrictions for employers to fire "noticeably" underperforming workers and allow companies to change employment rules more easily, as part of its reform drive.

The KCTU, which has more than half a million workers as its members, argues that the government's labor reform would end up making it easy for companies to fire workers, eventually worsening overall working conditions.

Hwang also said that the Ministry of Justice will bring criminal charges against those who stage illicit protests across the country.