Transport, health and other public services face severe disruptions Tuesday as workers take part in a 24-hour general strike called by Greece's two largest unions to protest the government's economic policies.
Authorities said flights and train service would be drastically cut, state hospitals would function with emergency staff, and schools, universities and tax offices would be closed all day.
Umbrella unions GSEE and ADEDY, representing private- and public-sector employees, called the general strike to protest recent legislation reforming the country's fragmented pension system.
The two unions between them represent some 2.5 million workers, about half of Greece's total work force.
Unions also demand more state social spending, as well as salary and pension increases, and oppose government plans to privatize state carrier Olympic Airlines.
Olympic has canceled 150 flights Tuesday — mostly domestic but including routes to London, Brussels, Rome, Frankfurt and Paris — while private Aegean Airlines is canceling 46 domestic flights. Air traffic controllers will hold a four-hour strike from noon.
The state railway company has canceled most train services Tuesday, while work stoppages will also hit Athens public transport.
Lawyers, journalists and civil engineers will also be on strike.