About 30 percent of senior citizens have not applied for refunds for medical expenses since a reimbursement system was introduced in October, according to a survey released Saturday by a group of doctors.

The unpaid refunds total 728 million yen, according to the survey, conducted by the Japanese Medical and Dental Practitioners for Improvement of Medical Care.

"There is a need to thoroughly inform senior citizens about the system and to take such measures as simplifying application procedures," the group said.

Under the system, set up to help people aged 75 and older, those who pay more than the set maximum amounts are eligible to receive refunds for the extra they paid by applying at the offices of city, town and village governments.

The refund system was introduced to reduce the burden of an increase in the amount people have to pay themselves under the public medical insurance scheme.

The survey, which covered 1,182 local governments in 21 prefectures, found that 30 percent, or 120,000, of the 400,000 eligible senior citizens have not applied for refunds.

Of the surveyed prefectures, Okayama had the lowest rate of people applying for refunds at 40.9 percent, followed by Kagoshima at 43.9 percent and Fukuoka at 45.9 percent

Aichi, which is notifying people who have not applied for refunds, had the highest rate of refunds, with 90.9 percent of those eligible applying.