The Cabinet Secretariat has urged government agencies to make information designated as secret under the controversial state secrecy law accessible to Japan's Board of Audit if so requested, a government source said Tuesday.

The Cabinet Secretariat sent a letter of notification on Dec. 25 to 20 administrative offices with the right to designate which information should be protected under the law, such as that of the Foreign and Defense ministries. The accounting watchdog was concerned that the withholding of sensitive information could obstruct its auditing process.

The Constitution states the final accounts of expenditures and revenues of the state shall be audited annually by the Board of Audit.

The accounting watchdog conveyed its concern in September 2013 to the Cabinet Secretariat that documents designated as secret may become inaccessible under the then-envisioned secrecy law, which it felt raises constitutional problems.

The Cabinet Secretariat said last month in the letter that government offices remained obliged to submit documents requested by the board, and that the secrecy law does not change that practice.

The contentious law was put into effect in December 2014 amid fears that people's constitutional right to know could be undermined in the name of protecting national security.

A total of 443 pieces of information were designated as secret under the law as of the end of last year, up 26 from the end of June, the government said Tuesday.

Of the 26 cases, 16 were designated by the Acquisition, Technology & Logistics Agency, affiliated with the Defense Ministry, and they are mainly related to information about aircraft and submarines of the Self-Defense Forces.

The remainders are four cases designated by the Defense Ministry, two cases each set by the Cabinet Secretariat and the Foreign Ministry, and one case each by the National Police Agency and the Internal Affairs and Communications Ministry.