Internal reserves held by a foundation operating the nation's only bone-marrow bank have swollen to more than 500 million yen, exceeding a government-set ceiling for a nonprofit entity, sources said Monday.

The Health, Labor and Welfare Ministry sent inspectors Monday to the office of the Japan Marrow Donor Program to look into the matter.

Patients with leukemia and other diseases who need bone-marrow transplants have said the foundation should allocate more of the reserves to help reduce their financial burden in treating the diseases.

A guideline set by the Internal Affairs and Communications Ministry stipulates that the amount of internal reserves by a nonprofit entity is limited to a maximum of 30 percent of its operating and administrative costs.

The bone-marrow bank operator is run on funds put up by patients and donations by the general public, as well as government subsidies.

The entity suffered deficits in its operating account for five years in a row through fiscal 2001, prompting it to dip into internal reserves and raise the amount of funds contributed by patients.

But in the following three years, the entity's reserves swelled due to increased government subsidies and the larger contributions by patients.

In fiscal 2005, its internal reserves are expected to amount to more than 500 million yen, exceeding the 30 percent limit, the sources said.

The Japan Marrow Donor Program was established in 1991 to run the bone-marrow bank.