Petrol bombs were thrown at the Athens home of the brother of Greece's government spokesman early on Sunday, causing minor damage but no injuries, police said.
Police blamed the attack on far-left protesters angry at a police raid last week that cleared a squat popular with anti-establishment groups. About 100 people were arrested during the raid.
"It's a reaction to the police operation over the last few days to evacuate various occupied buildings," said a police official.
In a statement, the conservative-led government's spokesman Simos Kedikoglou said "targeting our families and kids will only strengthen our will".