Some Japanese banks may soon come under the spotlight for potential "gender washing” over the way they count the number of women in management positions.

The Financial Services Agency found a big discrepancy in responses from a regional bank survey of female managers. One group of lenders reported that women hold less than 10% of management roles, while for another group in the same survey, it was closer to 20%, according to Tatsufumi Shibata, the senior agency official in charge of regional financial institutions.

"I wonder if there is a difference in how they define managers?” he said in an interview.