The Mita Labor Standards Inspection Office in Tokyo has filed criminal papers with prosecutors against Tokyo-based credit card firm JCB Co. and four of its executives on suspcicion of forcing employees to engage in overwork.

According to the office, which filed the papers on Thursday, the four executives forced seven employees in two departments to work overtime in Februrary and March last year for more than the legally permitted maximum of 80 hours a month, the longest exceeding the limit by some 67 hours a month.

The employees were paid for the overtime work, the office said.

The office had repeatedly urged the company to rectify the situation.

The four executives are 60-year-old and 56-year-old managing executive officers and 49-year-old and 56 year-old department heads, the office said, of the posts they held at the time of the incident.

JCB said in a statement that the firm launched a committee in July last year aimed at reducing working hours, and is working on cutting workloads and strengthening proper management.