Citibank Korea's union is taking steps to launch a strike.
The union said Friday it had submitted a petition to the National Labor Relations Commission (NLRC) to arbitrate an ongoing dispute with management.
If negotiations fail, the union said it will stage a walkout.
Industry sources say the chances of the two sides finding common ground during talks convened by the government's panel are slim.
"The petition to the NLRC appears to be a step by the union to secure justification for a strike," a source said.
The bank's union and management held 18 rounds of negotiations over salaries and benefits for employees, but failed to reach an agreement.
Other major issues in contention include management's plan to streamline the organization by conducting an early retirement program for hundreds of workers and close branches.
According to the union, the bank may cut up to 650 jobs through the retirement program. The bank conducted a similar retirement program in 2012, in which 199 workers left the bank. Management also plans to shut down 56, or 29 percent, of its 196 branches nationwide this year.
The union also asked the Financial Supervisory Service to inspect fees the Korean unit is paying to Citibank of the U.S. annually and the planned branch closures.
"These fees are paid for the parent firm's management advisory services. All local operations of global companies are paying these fees," a Citibank Korea official said. "This is a legal payment for its investment in the Korean market."
The official refused to disclose the exact amount of the fees.