Seoul: Unionized workers of Kakao Corp., South Korea's messenger app operator, are set to take a day off en masse on Monday in a sign of protest amid a continued gridlock in wage negotiations.

According to Yonhap News Agency, in their second collective action, unionized members are expected to stage what they called a "Log-out Day" by taking simultaneous annual leave. Some 3,000 workers from five units of Kakao, including its headquarters, Kakao Pay and Kakao Enterprise, are estimated to participate, industry watchers said.

Wage talks between Kakao's labor union and management have been at a standstill since May, after the two sides failed to narrow differences in performance-based incentives. The union is reportedly demanding the company pay around 13 to 14 percent of operating profit as bonuses, while the management has rejected such demands, claiming they put too much burden on the company.

On June 10, workers staged their first-ever strike. Some 1,500 union members walked out from their jobs for four hours and rallied near the company's headquarters in Pangyo, south of Seoul. Industry watchers are closely following the latest industrial action from Kakao's union and whether it could cause disruptions to the company's key services, such as the popular messenger app KakaoTalk.

Kakao's management said it plans to continue negotiations with the union, while remaining on standby to ensure stable service operations.