Hackers associated with the Anonymous collective posted a protest against Greece's EU and IMF-inspired austerity policies on the website of the country's Justice Ministry on Friday.
The site was taken offline until it was secure, a spokeswoman for the ministry said.
The Anonymous collective has been linked to attacks around the world aimed at punishing governments for certain policies or at showing that corporations' data security efforts are inadequate.
The hackers said they were protesting against the near-bankrupt country's bailout by the European Union and the International Monetary Fund which has been associated with unpopular austerity policies.
"You have joined the IMF against your people's acquiescence ... democracy was given birth in your country but you have killed it," said the hackers in English in a two-minute video that was posted on the ministry website.
Near-bankrupt Greece is currently locked in last-ditch talks with its creditors to stave off a chaotic default that might spill over to other euro zone countries.
(Reporting by Harry Papachristou; editing by Philippa Fletcher)