Amazon.com Inc.'s Japanese unit has been ordered by the Consumer Affairs Agency to take measures against the use of misleading "reference prices" on its retail site that could lead customers to wrongly conclude that the products being offered are bargains.

"It is regrettable that misleading representations have been found on one of Japan's largest online retail sites," an agency official said. "Reference prices must be a benchmark for consumers to judge if the price is high or not."

The online shop run by Amazon Japan K.K. displayed reference prices along with substantially lower sale prices for products such as sweet sake and brake oil, making them look like bargains, but the reference prices were actually higher than the products' sticker prices, the Consumer Affairs Agency said Wednesday.

The sweet sake carried a price tag of ¥956 ($8.4) per bottle along with a reference price of ¥3,780 between June and July, but the suggested retail price was actually ¥600.

For the brake oil, the online shopping giant showed a reference price of ¥4,640 from September 2016 through June this year, although the manufacturer's suggested price was ¥3,300.

The agency issued an administrative order against the Japanese arm of the U.S. online retailer to ensure it will not display such misleading prices again.