About 250 financial union leaders pledged to go on strike in September to thwart the introduction of the performance-based pay system and other measures that may result in layoffs, a union official said Wednesday.

On Tuesday, 83 percent of more than 95,000 unionized financial workers voted in favor of a strike.

The results of the vote illustrated that the resentment of unionized workers has reached a limit, said Oh Chi-hwa, a spokesman of the Korean Financial Industry Union.

Oh said the union members are set to stage a strike on Sept. 23 in protest of banks' plan to adopt the performance-based pay system.

The Korea Federation of Banks, a banks' lobby group, is set to announce guidelines for the performance-tied pay system this week.

The performance-based wage system is part of the government's efforts to boost labor flexibility to create more jobs, especially for younger generations. Some 120 public companies and institutions are in the middle of adopting the new wage program, with some of their unions protesting the move.

Korean banks have suffered declining margins due to record low interest rates and tough competition in the nearly saturated domestic market, and faced increased calls to adopt the new wage system to streamline themselves and go overseas to find a new growth driver.

The financial union workers staged strikes in 2000 and 2014. (Yonhap)