Authorities are investigating whether or not the prime minister’s website as well as other government officials, political parties sites have been hacked.

The police electronic crimes division was investigating whether they were the target of an organised attack by hackers.

The websites of prime minister Lucas Papademos, citizens protection minister Christos Papoutsis, the Greek Police and the Hellenic Parliament were among official websites that went offline.

Police said the problem occurred when the websites were bombarded by people attempting to access the websites simultaneously, causing the system to collapse.

Technical services succeeded in restoring the sites during the night, but some of those sites, including the police site, the sites of the mainstream Pasok and New Democracy (ND) parties, the finance ministry and finance minister and government vice-president Evangelos Venizelos, went offline again.