Computer hackers bring down PlayStation's worldwide network

The company said it had been forced to take down the PlayStation Network (PSN) while it investigated an "external intrusion".

The system, which allows users to surf the internet, play games and interact with other console owners, has been unavailable for five days since the hack was discovered. Users trying to connect have been met with error messages stating that the network is "undergoing maintenance" or is "suspended".

According to Sony, it has more than 70 million user accounts globally.

In a blog, Simon Seybold, the company's director of corporate communications and social media, said experts were "working around the clock" to bring the system back online.

He said: "Our efforts to resolve this matter involve re-building our system to further strengthen our network infrastructure. Though this task is time-consuming, we decided it was worth the time necessary to provide the system with additional security."

However, in an update to his message yesterday, Mr Seybold said that he could not give any definite timeframe for when the system would be up and running again.

It was initially thought that Sony has been hit by the hackers' group Anonymous - an online community who claim to be "fighters for internet freedom".

However, a blog connected to the group published a statement entitled "For once we didn't do it; Sony incompetent".

In the blog, the group said that while it could be that members of the collective had been acting independently, the group "was not related to this incident and does not take responsibility for whatever has happened".

The statement went on to suggest that the company was using previous Anonymous attacks to cover up "an internal problem with the company's servers".

Anonymous has attacked the Japan-based entertainment giant over its prosecution of George Hotz, a 21-year-old American hacker who unlocked the PS3's closed operating system and released the code, allowing users to play pirated games.

Internet and gaming industry expert Olly Mann said that he was surprised it was taking so long for Sony to get the system back online and that the problem was potentially very damaging for the company.

"The internet component of any console isn't an add-on any more," he said. "It's pretty important for all of them to have an online presence, so that users can download apps and talk to people. Even if its internet link was only down for an hour, it's damaging to the brand of Sony.

"Every time the PlayStation goes down and its rival the XBox doesn't will translate into a few more people buying XBoxes."