Greek seamen extended a strike to protest government austerity for a further 48 hours on Sunday, meaning that dozens of islands will have been cut off from the mainland for six days.
Farmers also briefly disrupted traffic on several major motorways across Greece in the latest wave of protest over budget cuts and labor reform that is needed to satisfy international lenders.
Greece's biggest labor union has called a general 24-hour strike for February 20.
The seamen are demanding months of unpaid wages and the repeal of a draft law that weakens their union by introducing a new employment contract between shipowners and crew.
"The law wipes out the seamens' profession and all the rules underpinning it," PNO union said.
The strike, which started on Thursday, has begun causing shortages on grocery shelves and is hindering agricultural exports to the Balkans and beyond, the Athens Central Vegetable Market Association said in a statement.
The farmers disrupted traffic with sit-ins and by distributing free rice to drivers, to protest tax increases that form part of the country's bailout.
"We have no choice but to go on, we're on the brink of desperation," one farmer told state television NET. Greece's latest austerity package mandates lower tax refunds and fuel subsidies for farmers and increases the social security contributions they must pay.
The Greek government is holding talks with the protesters but refuses to budge on any demands that might undermine its deficit cutting efforts, a condition of bailout funds and debt relief from the European Union and International Monetary Fund.
Greece last month invoked rarely used emergency powers to break a strike of subway workers, serving military-style orders instructing them to return to work or face arrest.
Austerity has fuelled social unrest and extremism. Police on Friday arrested two bank robbers who turned out to be members of left-wing extremist group "Conspiracy of Fire Cells", which has claimed a spate of bomb attacks across the country since 2009.
"Golden Dawn", an ultra-right, anti-immigrant party which ranks third in the opinion polls, staged its biggest rally ever in Athens late on Saturday, mustering about 5,000 supporters.