In the evening of June 20, the plenary session of the House of Councillors (HoC) passed the Amended Diet Act by a majority vote of the ruling parties and other parties. The amendments establish "Information Monitoring Committees" in both Houses to provide permanent oversight of the administration of the Act on the Protection of Specially Designated Secrets that will enter into effect in December this year. The committees will be set up at the same time as the Act on the Protection of Specially Designated Secrets.

The legislation was introduced by Diet members from both the LDP and the New Komeito. The monitoring committees of the two Houses will have eight members each, with positions assigned according to the seats controlled by individual factions. Meetings will take place behind closed doors and will investigate whether the designation and revocation of secret information are performed in an appropriate manner based on annual reports from the government and oral explanations from the heads of government agencies that designate secrets. Committees may issue advisories for the improvement of administration if they find problems.

In the House of Councillors Committee on Rules and Administration, which met prior to the plenary session, Ms. Mizuho Oonuma, a HoC member from the LDP questioned, noting "There is a possibility that if designated secrets are submitted to the Diet, ministries and agencies may refrain from making designations because they do not wish to share designated secrets. There need to be measures to ensure the flow of information within the government." She also emphasized the need for whistleblowing systems to ensure appropriate administration.