'Police have dedicated significant resources to this type of crime and will continue to do so, but at the end of the day, prevention is better than cure.'

The internet was providing more opportunities for criminals to access personal information, he said.

'The security of the major banks is of quite a high standard, but customers do have a responsibility to keep their passwords and other data secure. If you put a lock on your door, you have a responsibility to look after the key and use it properly.'

Mr Medwecki said social networking sites such as Facebook often contained enough information from which to obtain a fake identity.

'The amount of personal data that is placed on these networking sites is amazing,' he said. 'People must start thinking in these terms to protect themselves.'

Most identity frauds involve credit cards. Mr Medwecki said the police had encouraged the Hong Kong Association of Banks to improve card security by introducing the chip-and-PIN system used in much of Europe. Customers must input their PIN for every transaction but the card never leaves their sight, making fraud much more difficult.

Police strongly support the introduction of the system, fearing that if it becomes standard elsewhere but not in Hong Kong, international fraudsters will target the city for illegal transactions.

Mr Medwecki said the police appreciated banks had infrastructure and co-ordination issues to do with introducing chip-and-PIN technology, but it was 'the way to go'. He added: 'Everyone has to go over the one system at the one time otherwise there will be glaring gaps.'

Another common form of theft involving identity fraud is telephone deception scams, where a gang member phones and pretends to be a family member in distress. They convince the victim they are in trouble and need money transferred to a bank account.

Mr Medwecki said while customers should always be wary of phone calls asking for the transfer of money, banks could help by introducing better security for opening accounts. Gangs often paid money to drug addicts or teenagers to use their details to open bank accounts, he said.

Police have already passed some recommendations to the Hong Kong Association of Banks.

These include a 'cooling off' period before an account ATM card can be used, delaying the transfer of money between newly opened accounts and the prior registration of accounts to which money can be transferred.

Mr Medwecki said there had already been some significant police operations targeting identity theft but the problem would continue.

'These crimes are not one-off, opportunist crimes. They are organised activities involving sophisticated gangs. Long-term investigations are conducted and gangs are neutralised but as long as there are opportunities, it will continue.'