The Information Commissioner's Office (ICO) website has been taken offline following a suspected distributed denial of service (DDoS) attack.
The public-facing website does not contain any sensitive information, the information watchdog said.
"Access to the ICO website has been disrupted over the past few days. We believe this is due to a distributed denial of service attack," a spokesperson for the ICO said.
"The website itself has not been damaged, but people have been unable to access it."
He added: "We regret this disruption to our service and we are working to try to bring the website back online as soon as possible."
Despite a number of reports online claiming that a group with links to the Anonymous hacktivist collective is behind the attack, over what it believes is corruption in the Leveson inquiry into press standards, the ICO spokesperson said that this could not be confirmed.
Being unable to access the website may cause some problems for businesses that have not yet taken the necessary steps to comply with the new EU cookies law that comes into force next week (26 May).
Under the new regulation, all websites must allow visitors to be able to stop cookies being installed on their own machines, if they so wish on privacy grounds.
The ICO website hosts guidance for website operators on how to comply with the law, and failure to do so could result in a fine of up to £500,000.
Other cookies guidance, based on the information from the ICO, can be found on the International Chamber of Commerce website.