Greece's conservative-led government on Monday ordered maritime workers to end a strike that has disrupted ferry services to the country's myriad islands for nearly a week.
"The government made every possible effort to satisfy the maritime workers' demands," Merchant Marine Minister Costis Moussouroulis told reporters.
"Unfortunately, petty politics have left no room for dialogue," Moussouroulis said.
As a result, the government would issue requisition orders to force sailors back to work from 0400 GMT on Wednesday, the minister said.
The Panhellenic Seamen's Union (PNO) had earlier decided to extend the six-day mobilisation for another 48 hours.
"We have decided to continue with another 48-hour strike for every category of vessel," union had said in a statement.
And a senior unionist said seamen would resist the requisition order.
"We will tear up this order...we will take all necessary measures to safeguard our struggle," Antonis Dalakogiorgos told Real FM radio.
The PNO is protesting against a labour reform that allows ferry owners to limit the number of crew members.
The union claims that unemployment in the sector has hit more than 7,000 maritime workers, out of a total of 15,000 active workers.
The merchant marine ministry counters that there are 4,200 unemployed and 17,000 active maritime workers.
As the coalition government tries to implement a harsh austerity programme demanded by international creditors in return for vital rescue loans, it has had to deal with waves of strikes.
Riot police were sent in January to break a strike by Athens metro staff that had paralysed the network for nine days.
Farmers around the country have now parked their tractors near major motorways since last week, without disrupting traffic so far.
Over the past two weeks, mass transit workers and hospital doctors have also intermittently staged work actions.
Greece's two main unions, the public sector ADEDY and the private sector GSEE, have called a general strike for February 20.
Auditors from the troika of Greece's creditors -- the European Union, International Monetary Fund and European Central Bank -- are due in Athens at the end of the month to assess the reforms.