Unionized Seoul subway workers said Tuesday they will go on a full-scale strike on Dec. 6 to demand wage increases and new staff hiring.

The walkout plan was announced in a news conference by the biggest of the three labor unions of Seoul Metro, the operator of subway lines 1-8, in front of Seoul City Hall.

The strike, if carried out, will mark the third consecutive year of such action.

Concerns about significant railway service disruptions are rising further, as the Korean Railway Workers' Union, responsible for subway operations in the capital area and national train services, has also threatened an indefinite general strike early next month.

The Seoul Metro union, which represents 60 percent of the workforce, said its members will begin a labor slowdown and work-to-rule protests Wednesday as part of the broader strike plan.

According to company officials, the main disputed issues are wage and hiring increases. The company has offered a pay raise of 2.5 percent, but the labor union is demanding a higher increase. (Yonhap)