A 24-hour strike wave hit transports and services in Greece on Wednesday with unions protesting against a new round of reforms linked to the country's concluding third bailout.
The walkout disrupted flights and urban transport and knocked out train and ferry services as the busy tourist season gets underway.
Flight controllers are observing a three-hour stoppage to 1000 GMT, causing scores of flights to be rescheduled.
Protest rallies will be held in Athens and major cities later in the day.
Greece's leftist government is concluding the final audit of its third multi-million euro bailout package from fellow eurozone states, with the supervision of the International Monetary Fund.
A new bill containing the latest reforms demanded by creditors -- including the breakup of Greece's state-dominated energy sector -- is to be approved by parliament by June 14.
Athens hopes that a scheduled June 21 meeting of eurozone finance ministers will also greenlight the measures.
Nearly 50 general strikes have been held since the start of the Greek economic crisis in 2010.
The country signed up to three bailout packages -- in 2010, 2012 and 2015 -- but its economic recovery remains fragile.
Greece intends to return to financial markets after its third bailout officially ends on August 20.
But political turmoil in Italy is likely to increase borrowing rates, especially if concerns about eurozone stability persist.