The single biggest protest since Greece’s coalition government took power in June has paralysed Athens with the numbers demonstrating on the streets estimated to be in the region of 50,000.
The march organised by the two biggest trade unions is part of a 24-hour strike across the country.
It was called in protest at the latest round of belt-tightening measures.
“The measures the three-party government is taking are unacceptable and the people need to understand that without a fight they will never accomplish anything, otherwise this is a one-way street,” said one of the marchers, Marinoa Kazakis a private businessman.
Sporadic clashes in the capital have been reported with police firing tear gas at protesters who were throwing stones and petrol bombers.
Twice the number of police, compared to those on duty at previous rallies have been deployed in Athens where riots have broken out before.
The government is planning spending cuts of 11.5 billion euros as a pre-condition to the country receiving its next tranche of international bailout funds.