Retail giants Metro and Wal-Mart say that some of their Shanghai outlets have similar product pricing problems as Carrefour, which has been fined for cheating customers.

The companies told Shanghai Daily yesterday that they would offer refunds for customers who had been overcharged and would regulate price tags more strictly in future.

Xinmin Evening News reported that the two companies had displayed bogus prices or misleading tags and had charged customers higher prices at the check-out.

A customer surnamed Shi told the newspaper he had been charged 49.90 yuan (US$7.58) for socks with a 39.90 yuan price tag at a Metro store in Putuo District.

Staff said the mistake was due to negligence - failure to change the price tag after a discount period had ended several days before, according to the newspaper.

A Metro spokesman said that some "minor problems" had been discovered since the supermarket launched self-checks last Wednesday and the mistake might be one of them.

"There are some 20,000 tags in each outlet and we feel ashamed if something goes wrong," said spokesman Chen Libin.

He encouraged customers to double check their payment vouchers and said that the company would "make up customers' losses" if a mistake was confirmed.

"We will also improve our IT system and staff training to avoid pricing problems in the future," Chen said.

Another customer, surnamed Ge, accused a Wal-Mart outlet, also in Putuo District, for charging 26.90 yuan for a bottle of sesame oil priced at 19.90 yuan.

The newspaper said a computer problem had caused the mistake but a Wal-Mart's spokesman told Shanghai Daily it was a mistake in placing products.

"A larger bottle of the oil was placed on a tag for smaller ones," spokesman He Wenying said.

The outlet has agreed to offer full refunds for customers affected by the company's mistakes. But the two companies said they would not pay extra compensation unless ordered to by local authorities to prevent abuses.

"The customer surnamed Shi was angry because we turned down his requirement for 1,000 yuan in compensation," Chen said.

Bei Liheng, of Shanghai's Development and Reform Commission, said it had received no customer complaints about supermarkets other than Carrefour, three Shanghai outlets of which were each ordered to pay a fine of 500,000 yuan (US$75,954) on Friday for price frauds such as indicating false discounts and charging higher amounts at the check-out than on price tags.

"We will conduct investigations as soon as we receive complaints from customers," Bei said yesterday.