Greek unions started a 48-hour strike on Tuesday over planned austerity measures.
Employees from a wide range of sectors are taking part, including taxi drivers, civil servants and transport workers.
The walkout comes ahead of a parliamentary vote this Wednesday on fresh spending cuts to qualify for more bailout aid.
Aleka Papariga, a Communist MP, said: “We need resistance to the government and this system.”
Dimitris Yanoulas, a striking private sector worker, said it was difficult for Greeks to find work.
“To work for 12 hours on half the salary and the risk of being fired hanging over your head, this is not work, it’s forced labour,” he said.
“To live with 400 euros with the needs that a family has, and not just a family, a single person cannot live with this money.”
But ministers say the wage and pension cuts will save 13.5 billion euros over the next two years.
If MPs vote against the new cuts, the country’s international lenders could cancel its next installment of rescue money.