Mizuho Bank said Friday it has failed to process some 300 money transfer requests following a temporary system failure the previous day that was its ninth this year.

The trouble occurred despite the bank, a unit of Mizuho Financial Group Inc., having pledged to prevent similar failures after Japan's financial authorities ordered it to improve operations in November.

Customers were unable to make money transfers between banks through Mizuho's internet banking and automated teller machines for about an hour starting around 3:30 p.m. on Thursday. The bank said it had received about 2,700 transaction requests during the period, but could not process them all that day.

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The bank attributed the failure to human error in system settings regarding transactions at night and on holidays.

The affected customers will be notified individually as to how their requests will be handled, according to Mizuho.

The bank has been hit by eight system failures from February to September this year, temporarily suspending transactions for about 80 percent of its ATMs in one case. The series of system failures led to the replacement of top executives.