Wednesday's vote is the biggest test yet for the government of Prime Minister Antonis Samaras, which needs victory to secure aid from foreign lenders but has failed to convince its smallest coalition partner and the public to back the reforms.

The strike, called by Greece's two biggest labor unions representing half the four million-strong workforce, brought public transport to a virtual standstill and shuttered schools, banks, and local government offices.

It was the third major walkout in two months against the package of public spending cuts and reforms making it easier to hire and fire workers.

Successions of strikes since Greece fell into crisis in 2009 have so far failed to prevent parliament approving the cuts demanded by the international lenders which have inflicted misery on the country and kept the economy in a deep recession.

The government has implored Greeks to endure the cuts to avoid national bankruptcy and promised this will be the last round of pain. Greeks, who have seen many such promises broken before, have responded with a mix of resignation at their fate and anger at their political leaders.

"They should go to hell and beyond," said Anais Metaxopoulou, a 65-year-old pensioner. "They should ask me how I feel when I have to go to church to beg for food. I wouldn't hurt a fly but I would happily behead one of them."

Parliamentary approval for the package — which includes slashing pensions by as much as a quarter and scrapping holiday bonuses — to ensure Greece's European Union and International Monetary Fund (IMF) lenders release more than 31 billion euros ($40 billion) of aid, much of it aimed at shoring up banks.

With 16 deputies from the small Democratic Left planning to vote against reforms and a non-commital response from at least five Socialist deputies, Samaras can count on the support of only about 154 lawmakers in the 300-seat parliament.

Any further defections from the Socialist PASOK party could put the government at risk of falling below the 151 votes needed to pass the measures, ushering in political chaos that would once again raise fears of a Greek eurozone exit. 

NOTHING LEFT TO CUT

Trains, buses and the subway came to a halt as the strike began. Many flights have been canceled, ships remained tied up at ports, and taxi drivers also stayed off the streets.

"We're calling on every lawmaker in parliament, without exception, and we're telling them that 100 percent of workers in the public sector are saying that they should not vote for these measures," said Ilias Iliopoulos, head of public sector union ADEDY, which called the strike with private sector union GSEE.

Police beefed up security for midday rallies in Athens that often end in small-scale rioting and clashes with hooded protesters. About a dozen police vans were on standby around the main square outside parliament.

Greece has gone through several rounds of austerity that has helped to shrink its economy by a fifth since the debt crisis exploded but failed to get its finances back in order.

The country's public debt is seen at a whopping 189 percent of gross domestic product next year and Athens is expected to be widely off track from targets under its latest bailout agreed with the troika of the IMF, the European Commission, and the European Central Bank.

Some Greeks say the latest cuts could tear society apart.

"Someone needs to tell them there's nothing left to cut," said Vassilis Dimosthenous, a 50-year-old construction worker who has been without a job for 10 months. "They've made our daily lives unbearable. If only I was 10 years younger I'd leave this place."