Greek public sector workers walked off the job on Wednesday in protest at new austerity measures and layoffs demanded by foreign lenders, disrupting transport and shutting schools and tax offices.
The 24-hour strike is the latest in a series of protests since September against a package of wage cuts and tax hikes demanded by Greece's European Union and IMF lenders as the price for bailout loans to keep the country afloat.
Striking teachers, doctors and municipal workers started gathering in central Athens as part of the walkout called by the ADEDY union, which represents about half a million public sector workers or roughly a quarter of the country's work force.
"We want to tell the government enough is enough! Enough with layoffs, wage and pension cuts, the collapse of the public sector, enough with these tax hikes," said ADEDY unionist Despina Spanou. "People are fed up and they'll show their rage."
Thousands were expected to march to the administrative reform ministry which oversees public sector reform, though turnout may be smaller than protests held before the austerity package was passed in parliament last month.
The measures – which include earmarking 27,000 civil servants for eventual dismissal – remain deeply unpopular among Greeks who say society is crumbling under the weight of spending cuts and tax hikes that hurt mostly the middle class.
"We demand that the government changes these unjust policies that hurt workers and kill the public sector," said ADEDY chief Costas Tsikrikas.
But the rallies have lost some of the momentum since the austerity bill was approved and Athens received long-delayed funds from its foreign lenders, averting the risk of bankruptcy that had hung over the country for months.
Unions also say that some Greeks although fed up with austerity could no longer afford to lose a day's wages by taking part in strikes.
Greece's other major union, the private sector union GSEE, said it would hold a three-hour stoppage in solidarity and join the march through the streets of central Athens. The Communist-affiliated PAME group was expected to hold a separate rally.
Some domestic flights were grounded and about 100 workers occupied the headquarters of Athens' city train company on Wednesday in protest at planned wage cuts.
Train workers also started a 48-hour strike against the conservative-led coalition's plans to privatize Greece's national railways. Metro and tram workers walked off the job for a few hours on Wednesday and plan a 24-hour strike on Thursday.
Police deployed about 2,000 officers in central Athens, but officials said they did not expect serious violence.
Major protests are often marked by small-scale clashes with groups of hooded protesters throwing stones and petrol bombs at riot police who respond with teargas.
The government has implored Greeks to endure the cuts and promised they will be the last, but that has convinced few in a nation where unemployment has topped 26 per cent and poverty levels have soared.
"We, the unemployed, will never see the bailout funds in our pockets," said Stavroula Kandelanou, 34, a mother of two who is jobless. "They keep talking about growth but I don't see any."