D&A LLC represented KEPCO Engineering & Construction Company, Inc. (“Client”) in a lawsuit seeking confirmation of employment status and payment of wage differentials (Supreme Court 2021Da289191 Rendered on September 4, 2025), ultimately prevailing on nearly all claims.

Under the Act on the Protection of Temporary Agency Workers (“Act”), employees of partner companies (“Plaintiffs”) sought the confirmation of their employment status, claiming that they were in a temporary agency relationship with the Client, the prime contractor. The Plaintiffs also sought payment of wage differentials, arguing that they should have been entitled to the same working conditions as the Client’s regular employees performing the same or similar duties.

From the first instance through the Supreme Court, all levels of the court recognized that the Plaintiffs were temporary agency employees. Representing the Client, we argued that even if the Plaintiffs were deemed employees of the Client, the appropriate point in time for selecting comparable regular employees under the former Act was the moment of deemed employment, demonstrating that at that time, the Client had no regular employees performing the same or similar duties. Relying on the Supreme Court’s prior ruling (Case Nos. 2019Da223303 and 2019Da223310, rendered on March 12, 2024), we further contended that in the absence of comparable regular employees at the time of deemed employment, the Plaintiffs’ working conditions should be applied in a manner that does not reduce their pre-existing conditions. Accordingly, we demonstrated that it was reasonable for the Client to continue applying the separate working conditions initially applicable to the Plaintiffs.

Both the appellate court and the Supreme Court accepted our arguments. The courts held that (i) comparable regular employees under the former Act must be considered as of the time when the Plaintiffs were deemed the Client’s employees; (ii) no such comparable employees existed at that time; and (iii) the Client had established and applied separate working condition regulations for non-regular employees to the Plaintiffs. Accordingly, the courts ruled that the Plaintiffs were not entitled to the working conditions of regular employees, and that applying the separate regulations was lawful. Therefore, the courts found no basis for the Plaintiffs’ claims for wage differentials premised on regular workers’ working conditions and dismissed all such claims.

This case is expected to have a significant impact on similar pending cases involving the Client, as well as on analogous disputes involving other corporations and public enterprises. In particular, this case is likely to be frequently cited as a leading precedent regarding the timing at which temporary agency workers were deemed directly employed by an employer under the former Act.

The Supreme Court has reaffirmed that, when workers are deemed directly employed by an employer or subject to mandatory employment, their working conditions should, in principle, be determined through consultation between labor and management, provided that such conditions are not less favorable than their prior ones. If such consultation fails to reach agreement, the court may, at its discretion, determine reasonable working conditions based on its standards. This case is significant because it clearly confirms the Court’s approach to determining the working conditions of deemed employees under the Act.