Greek unions planned protests in Athens and other cities on June 11, hours after Prime Minister Alexis Tsipras said the negotiations over the country's bailout should be stepped up.
A small group of activists from the pro-Communist PAME trade union occupied the finance ministry early Thursday morning.
The workers took down the EU flag and hung a giant banner on the facade of the building overlooking Syntagma square in central Athens.
The banner depicts former prime ministers George Papandreou, Antonis Samaras and current premier Alexis Tsipras and reads "We have bled enough, we have paid enough".
State TV channel ERT reported that the occupation was "symbolic and peaceful", with about 150 demonstrators gathered outside the ministry in the early morning.
Alongside PAME, public sector umbrella union ADEDY called for a massive demonstration outside the finance ministry in Athens, in a sign of growing discontent regarding economic measures demanded by Greece‘s creditors. Rallies will also be held in 59 towns across Greece.