The country's integrated system for bankcard transactions, which is run by China Unionpay, broke down yesterday morning and was only partially up and running early yesterday evening.

"Trans-bank transactions are interrupted since 10:56am on April 20 due to a break-down of China Unionpay's network and main server," the Shanghai-based company said in a statement published on its Website yesterday.

The breakdown affected the city's largest shopping malls, restaurants, and a majority of stores along the Nanjing Road Pedestrian Mall.

Xiao Yao, a 25 year local, planned to buy a yellow jacket at the Super Brand Mall in Pudong' Lujiazui area around noon, but couldn't as her bank card wouldn't work and she didn't have enough money on hand to buy the jacket. A trip to the ATM probably wouldn't have helped as most bank machines were down as well.

Shop assistants across the city complained that sales were way down because of the problem.

"I was annoyed to know that I can't pay the bill after squeezing my lunch time and spending 30 minutes walking for nothing," said Lilian Li, who tried to pay her telephone bill with a credit card at a China Mobile outlet in Huangpu District.

Unionpay posted a statement just before 6pm yesterday saying the system was back up at most affected stores and banks.

"We are sorry for the inconvenience we have brought to card holders, institutions and shops," Unionpay said.

The company didn't specify the affected areas and gave no reasons for the technical failure. A Unionpay official only referred the areas as "those that Unionpay covers."

The problem also affected stores and shoppers in Beijing, Hangzhou, Shenzhen and Xiamen, among other cities.

More than 920 million bankcards, including debit and credit cards, were issued in China by the end of last year, according to Unionpay.