The government plans to take the unprecedented step of forcing depositors to observe the 10 million yen legal limit on postal savings, government sources said Tuesday.

The Public Management, Home Affairs, Posts and Telecommunications Ministry and Japan Post intend to use the savings that exceed the cap to purchase government bonds, as is legally required but never done if depositors refuse to observe the ceiling, the sources told Kyodo News.

The purchased bonds will be kept under custody of Japan Post, a government corporation created in April to take over the Postal Services Agency's postal savings, mail delivery and insurance services.

The measure will likely be implemented under the Postal Savings Law within the current fiscal year, which ends March 31, and is apparently aimed at mitigating criticism from private financial institutions that claim the legal limit of 10 million yen per individual has long been flouted.

Japan Post combines the balance of accounts held by the same person three times a year to check the amount of savings of each individual.

The combined amount of such "over-limit" postal savings were estimated at around 2.5 trillion yen for the year that ended last March 31, with about 1.29 million people involved.

Most agreed to reduce their savings below the legal limit, and the combined amount of such excess savings fell to 500 billion yen with some 210,000 people involved at the end of last month.

Under the Postal Savings Law, depositors are told to reduce their savings in the event they surpass 10 million yen each.

The government is allowed to purchase government bonds by using depositors' over-limit savings if they fail to comply within a month. These bonds are due to be kept by Japan Post and sold on demand by depositors, who would subsequently receive the proceeds.

The postal ministry and Japan Post plan to invoke the mandatory step, starting with depositors who have left their savings above the ceiling for an extended period, the sources said.

The move comes at a time when the postal savings system has come under fire from business lobbies and private financial institutions amid debate over a plan to fully privatize the postal services.

The Japan Association of Corporate Executives (Keizai Doyukai) has been calling for a sharp reduction in the savings limit, arguing the current situation is an example of public-sector operations weighing on private-sector businesses.

Thus far, the law has not been enforced because, government sources said, of the need to take complicated procedures and due to postal authorities' consideration for depositors, who are customers of government services.