More than 300,000 Kiwis could be vulnerable to scams and identity theft by hackers who attacked Sony's PlayStation Network.
Police are advising people to contact their banks after Sony revealed credit card details may have been stolen by the hackers accessing personal information including names, addresses and birth dates.
There was no evidence that credit card details were taken, Sony said yesterday, but it could not rule that out.
Detective Senior Sergeant John Michael said people concerned about unauthorised use of their credit cards should let their banks know their cards may have been compromised.
Those with PlayStation Network accounts needed to be vigilant in the weeks ahead. "Parents of children who have accounts should talk with their kids and alert them to the possible risks following the mass hacking."
Police in Australia have told people to consider cancelling their credit cards, and warned that the hackers had enough personal information to take out loans in people's names and commit identity crimes.
Netsafe director Martin Cocker said there was nothing people could do to protect themselves from identity theft once their personal information had been stolen.
The network – which lets PlayStation 3 and PlayStation Portable owners play multiplayer games and buy games, movies and music online – has been down since the attack last week, frustrating gamers, including students on their school holidays.
Alan Bell, editor of gaming website NZGamer, said gamers were pretty annoyed.
"Some are saying they're entitled to some level of compensation and there's a lot of people who are worried about having lost some of their private information to a hacker.
"We're advising our users if they're at all concerned that now is probably a good time to be talking to their credit card issuers."
Gamers took to online forums to express their anger at the outage and criticised Sony for taking a week to tell them of the breach.
Sony, which said the attack potentially affected all PlayStation Network users and members of its Qriocity music streaming service, said it became aware of the scope of the breach only on Tuesday.
The network has 77 million registered users worldwide, but Sony could not say how many were in New Zealand.
Mr Bell said New Zealand was known as a "PlayStation nation", and most people with a PlayStation 3 or PlayStation Portable would be using the network, which is free.
PASS THE WORD
What's been stolen
Names, addresses, email addresses, birthdates, PlayStation Network and Qriocity usernames and passwords, and online IDs.
Profile data, including purchase history and billing address, and password security answers may have been accessed.
Credit card details may also have been stolen.
What you can do
Contact your bank if concerned about your credit card.
Monitor use of your credit card.
Be alert for scams and do not give out any details to anyone claiming to be from Sony.
Change username and password once services are restored.
Change username and password on other sites if they are the same.