Unionized workers at three branches of Seoul National University Hospital went on strike early Wednesday morning, demanding a pay raise and better working conditions.

The action came after the labor and management of the hospital failed to reach a deal on the demands. It is the first time in six years that the hospital's labor union has taken the collective action.

"With the minimum level of manpower remaining at work for critical services, including the emergency and intensive-care rooms, 350 to 400 members of the 1,400-member union have launched a general strike," a union official said.

The walkout involved administrative, technical, housekeeping and food service workers who work alongside registered nurses and doctors in caring for patients at Seoul National University Hospital in central Seoul, SNU Healthcare System Gangnam Center and SMG-SNU Boramae Medical Center, the official said. Doctors and nurses are not participating in the strike, he added.

Despite the strike, the union has offered to continue negotiations, the official added.

Striking workers claim management is calling for a freeze in wages even though the hospital has been profitable in recent years.

The management denies that, saying freezing workers' pay is necessary due to worsening financial conditions of the hospital in Seoul. (Yonhap News)