Railway and subway unions warned on Tuesday that they will launch consecutive strikes on December 11 and 12 after failing to narrow gaps with management, sparking concerns about major disruptions to daily commutes and year-end travel.

The Korean Railway Workers’ Union announced at a rally near Seoul Station that it would start a full strike on December 11 unless management meets its core demands of restoring performance-pay standards, integrating high-speed rail services and implementing stronger safety measures.

Union leaders also accused the government of ignoring workers’ concerns, arguing that the current system, which bases performance pay on 80 percent of base salary, must be overhauled.

They pledged a "firm and unshakeable" strike if negotiations break down.

Unionized workers at Seoul Metro, which operates subway Lines one through eight, have declared a December 12 walkout, while the union for Line nine warned it will strike from December 11 unless the city fulfills earlier promises to increase staffing.

If the strikes proceed, significant disruptions are expected across both national rail services and the Seoul subway network, which combined carry millions of passengers daily.