Seamen in Greece have extended an ongoing strike for two days, causing food shortages on some Greek islands and further disrupting regional trade.
Many lorries have been stuck since Thursday
Hundreds of lorries with perishable supplies remained stranded at Greek ports and there were reports of clashes between angry farmers and the strikers.
The government said several navy ships had been put on standby to transport supplies if needed.
The strike, about unemployment benefits and pensions, was launched on Thursday.
"This is a very serious issue which concerns not only the seamen but the farmers whose produce... is being destroyed because of the delays," government spokesman Theodoros Roussopoulos said.
Farmers on Crete stormed into the port of Heraklion on Sunday, demanding an end to the strike.
The farmers surrounded striking ships, trying to cut ropes keeping ships at port.
"This is a catastrophe for us. Goods are rotting," Thanasis Kakos, president of the Greek International Lorry Drivers Association, was quoted as saying by Reuters news agency.
The strike also disrupted regional trade, with hundreds of lorries being trapped at Italian ports.