The Greek government invoked emergency legislation on Tuesday to order striking seamen back to work, threatening to arrest them unless they ended a walkout that has cut off dozens of islands from the mainland and caused shortages on grocery shelves.
This is the second time in a week that the government has taken such action to break a strike as Prime Minister Antonis Samaras tries to show his resolve to stick with unpopular reforms and wage cuts demanded by international lenders.
"Unfortunately, there is no room for further discussion," Shipping Minister Costis Mousouroulis told reporters.
The seamen, who are demanding months of unpaid wages and the repeal of a draft law that weakens their union, said they would extend the six-day strike by a further 48 hours.
"Trucks carrying products have been trapped in ports in Piraeus, Patras, Igoumenitsa but also in Italy," Greece's retail federation ESEE said in a statement.
The strike, which started on Thursday last week, is the latest test of resolve that Greece's fragile coalition government is facing.
Hundreds of seamen started rallying at the country's largest port in Piraeus to protest the order. Coastguard officials were expected to serve the strikers with military-style marching orders later on Tuesday.
Greek law allows the government to forcibly mobilise workers in the case of civil disorder, natural disasters or health risks to the public. Governments have been making increasing use of these powers to cope with anti-austerity strikes after Athens entered an EU/IMF bailout in 2010.
The measure was last used last week to break a nine-day walkout by metro workers.
Get all the latest news and videos in your inbox. Register FREE