Japanese electronic giant Sony has warned users of its PSN online gaming network that their personal data has been stolen by hackers.

Sony switched off PSN, which allows customers to purchase games and play online, a week ago following "an external intrusion on our system".

But the company claims that the fact that hackers had stolen customer data only came to light this week.

In an official blog post yesterday, Sony said the intruders had obtained PSN users’ names, addresses, birthdates, email addresses and log in details. "It is also possible that your profile data, including purchase history and billing address … may have been obtained," the company wrote. "While there is no evidence at this time that credit card data was taken, we cannot rule out the possibility."

It said it had appointed an "outside, recognised" security firm to investigate the breach, and taken steps to enhance the security of its network infrastructure.

In January of this year, Sony said PSN had 60 million registered users.