Greek public-sector workers went on strike on Thursday to protest labour and pension reforms and state asset sales which the government agreed with the country's official creditors in exchange for loans.
State hospital doctors, school teachers and municipality workers joined the nationwide strike called by Greece's main public sector union ADEDY. Ships remained docked at ports as part of a separate 24-hour walkout called by seamen.
"Workers and the poor are always the ones to pay the cost of the crisis," ADEDY said in a statement.
Striking workers and pensioners were expected to rally in central Athens later in the day. Participation in labour action has been low in recent years.
The seven-year economic crisis and an austerity-induced recession have driven thousands out of work and squeezed wages.
ADEDY's walkout is a prelude to a nationwide strike called by private sector union GSEE, Greece's largest, on Dec. 8.
Athens is still at odds with its lenders - the European Union and the International Monetary Fund - over unpopular labour reforms, as part of Greece's second bailout review.
Greece wants a swift conclusion of the assessment to qualify for more debt relief and inclusion in the ECB's bond-buying programme, which will allow it to regain market access before 2018. But Prime Minister Alexis Tsipras said on Wednesday Athens could not accept "irrational" demands.
Other sticking points in the negotiations which hit a snag this week are fiscal targets and reforms in the energy sector.
Labor unions have strongly opposed the sale of utilities, including a stake at power company PPC. Shareholders at PPC were expected to meet on Thursday to approve the sale of a 24 percent stake in power grid operator ADMIE to China's State Grid, a key privatisation deal under the bailout.