The strikers, who account for about half of the subway company's 250 workers, were to operate 100 percent of the scheduled train runs during the morning rush hours, 80 percent from 5-7 a.m. and 60 percent during the remaining hours.

The strike could affect the operation of the first section of the subway, which is operated by another company, Seoul Line 9 Operation Co., if scheduled train runs on the second and third section are delayed.

The subway company and the Seoul metropolitan government will put in substitute workers so that the operation of the subway is maintained at its usual levels.

The operator of the subway also said Line No. 9 will be run from 5:30 a.m. through 1 a.m. the next day, as before the strike.

In case the operation rate should fall below 90 percent, the Seoul regional government will operate 57 reserve vehicles on 46 city bus routes in the South Korean capital, among other measures. (Yonhap)