Mitsubishi UFJ Financial Group Inc.'s main banking unit was among five Japanese lenders downgraded by Moody's Investors Service after it cut the nation's credit rating.

Bank of Tokyo-Mitsubishi UFJ Ltd., Mitsubishi UFJ Trust and Banking Corp., Sumitomo Mitsui Banking Corp., Shizuoka Bank Ltd. and Chugoku Bank Ltd. were all cut one level to A1 with a stable outlook, Moody's said in a statement Tuesday.

Moody's on Monday lowered Japan's rating to A1, the fifth-highest grade, citing uncertainty over whether Prime Minister Shinzo Abe's administration will achieve its deficit-reduction goals and succeed in boosting growth.

"The rating actions reflect Moody's view that in Japan the capacity of the government to support banks is best measured by its own debt rating," the U.S. company said Tuesday.