Yasuo Fukuda, the top government spokesman, said Thursday that credit-rating agencies such as Moody's Investors Service Inc. have underestimated Japan's economic strength.

"The current ratings on Japan's government bonds do not properly reflect our economic power," the chief Cabinet secretary told reporters.

Ratings, however, are designed to reflect the level of investor risk.

Fukuda's comments followed Moody's announcement Wednesday that it had upgraded the long-term ratings on Italy's foreign and euro-denominated debt from Aa3 to Aa2.

The upgrade makes Japan, with its Aa3 rating, the lowest-rated country among the Group of Seven countries.

Japan may soon lag even further behind, as Moody's is expected to soon downgrade Japan's debt rating.

"That's why the Finance Ministry complained" about the low ratings recently given by major ratings agencies, Fukuda said.

He was referring to letters of complaint Haruhiko Kuroda, Japan's vice finance minister for international affairs, recently sent to Moody's, Standard & Poor's Corp. and Fitch Ratings.

"Moody's did not downgrade Japan's ratings this time," Fukuda noted, adding it is not really his place to comment on a private company's ratings on a country's government debts.

Fukuda also said he does not expect Japan's economic woes to trigger a disruption in the world economy.

Japan needs to map out additional measures to strengthen its economy, which has recently been bottoming out, Fukuda said.