The financial watchdog agency is set to carry out a check on how 15 major banks have evaluated the status of their loans to large corporate borrowers, a top financial regulator said Thursday.

After the inspection, the Financial Services Agency, banks and auditing firms "will thoroughly discuss whether the creditworthiness categories assigned to borrowers should be changed," FSA Commissioner Shoji Mori said in a lecture in Tokyo.

"It will be impossible for us to speedily reach conclusions on such changes."