A sign at Seoul Station in the capital informs rail passengers about possible delays, Sunday, due to a planned "work-to-rule" protest by the Korean Railway Workers' Union starting Monday. Yonhap

Korean railway workers will kick off a "work-to-rule" protest this week to demand higher pay and a bigger workforce, railway officials said Sunday.

The Korean Railway Workers' Union said it will launch the work-to-rule industrial action starting Monday, which could cause delays in some train services.

Delays are highly likely on subways in the capital Seoul area while regular and KTX high-speed trains could also be affected by the slowdown, according to Korea Railroad Corp.

The union plans to launch an indefinite strike early next month, demanding the addition of workers and an increase of 2.5 percent in basic salary. (Yonhap)