McDonald's Co. (Japan) said Monday that some of its outlets subjected consumers to double the correct level of consumption tax on Thursday after failing to modify their cash registers following the introduction of a new pricing system.

The blunder affected 22 McDonald's restaurants in 15 prefectures, resulting in 9,061 yen too much being paid by 255 customers. The company said it will refund the money if the customers take their receipts back to the same restaurants.

A new regulation on tax-inclusive pricing took effect Thursday, the first day of fiscal 2004, making it mandatory for retailers and service providers to display price tags including the 5 percent consumption tax.

According to McDonald's Japan, the 22 outlets levied an additional 5 percent on amounts that already included the tax.

They noticed the mistake and started to collect the right amount of tax later that day, it said.