A general strike has been called across Greece as protests against planned spending cuts and tax rises continue.
Trains, planes and ferries are at a standstill as transport workers join public sector workers who began their own 48-hour strike on Tuesday, the BBC reports.
Austerity measures planned in return for a 110 billion euro international rescue package for the debt-struck economy have sparked widespread anger.
The Greek parliament is to vote on the measures by the end of the week.
The measures include wage freezes, pension cuts and tax rises. They aim to achieve new budget cuts of 30 billion euros over three years, with the goal of cutting Greece's public deficit to less than 3% of gross domestic product by 2014. It currently stands at 13.6%.
Flights in and out of Greece stopped at midnight, and trains and ferries were not running early on Wednesday. Schools, hospitals, and many offices are expected to remain closed.
A mass rally is planned in central Athens before protest marches pass through the city.
The shockwaves from Greece's crisis are continuing around the world, with Asian stock markets following the slide in European and United States markets.
Meanwhile, the German parliament has begun considering the bail-out plan for Greece.
Chancellor Angela Merkel will defend her government's decision to take part in the deal agreed by European finance ministers, which requires Germany to pay the largest proportion of the loans to be made available to Greece.