Thousands of Greek pensioners demonstrated in central Athens on Thursday against cuts demanded under an international bailout, and the public sector union called its second nationwide anti-austerity strike in under a month.
The biggest public and private sector unions, representing about 2.6 million workers, plan a 24-hour strike against pension reform on Dec. 3.
The unions brought thousands to the streets earlier this month in the biggest domestic challenge to Prime Minister Alexis Tsipras since he was elected in January.
The government has passed legislation raising the retirement age, increasing health care contributions and scrapping most early retirement benefits. It also plans to merge several pension funds into one and cut back on supplementary pensions.
ADEDY, the public sector union, described the move as "the final blow to social insurance."
"Society, which has suffered brutally from the bailout, will overturn the austerity measures," it said in a statement.
Greece's economy is forecast at best to stagnate this year and contract mildly next year.
The government's majority has shrunk to just three seats as it pushes through the latest set of austerity measures but, in return, it has received money from the eurozone to recapitalise its four biggest banks.