BANKS should tighten up the way they run automatic teller machines (ATMs) if they want to keep their customers' confidence, the Consumer Council said last night. The call for change follows complaints from customers that some cash machines had handed out not enough money or none at all. The council's chief complaints officer Martin Wong Kwai-poon said: ''There should be some standard way of treating and addressing this problem so that the banks could tell people what would be done in such situations. ''It would increase public confidence in the banks.'' In a written statement at Legco this week the Secretary for Financial Services, Michael Cartland, said there was ''no specific industry-wide regulation on the functioning and maintenance of ATMs''. United Democrat councillor Dr Huang Chen-ya who tabled the original question said he was disappointed but not surprised by the answer. ''It was just a stock response which shows they have not really thought about the issue.'' He said electronic cards were getting more and more important, and some card transactions could involve many thousands of dollars. ''We plan to get this issue on the agenda of Legco's finance panel,'' he said. The Consumer Council and the Hongkong Bank both said they dealt with only a handful of complaints each year, but Dr Huang said that might just be the tip of the iceberg. ''If it was a small sum of money most people would not be bothered to go to all the trouble of complaining, and I am sure not all of them approach the Consumer Council for help.'' There are two main ATM systems in Hong Kong. The Hongkong Bank and the Hang Seng Bank together run 800 ATMs, while 43 banks are members of Joint Electronic Teller Services (Jetco) which runs more than 1,000 further ATMs in Hong Kong, Macau and Shenzhen. In a separate development Jetco yesterday revealed that it kept a ''blacklist'' of what it called ''unreasonable'' customers who complained about ATM transactions. Jetco general manager Tse Tak-heung said: ''There may be some kind of cheating by customers. ''When the customer is not reasonable or completely unreasonable then their name would be left with Jetco in case any other member banks should want to see it. ''We have a file here for the banks if they want it, but it is up to the banks what they do with the information. So far there are less than 10 names on it. ''When a complaint is made, at the end of the day staff at the bank will open up the vault behind the ATM to check if the amount of money paid out is correct.'' He said if the amount was not correct the cardholder's bank would make a full refund. But he said often the amount was correct, and security was so tight it would have been impossible for bank staff to commit fraud.