Two unionists were arrested at Piraeus on Friday morning for preventing the departure of a passenger ferry as part of a protest over unpaid wages.
The members of the Panhellenic Union of Merchant Seamen (PENEN) were taken into custody after the intervention of a prosecutor, which was prompted by the failure of the Penelope ferry not departing for its usual sailing, which takes in the islands of Andros, Tinos and Myconos.
Passengers had to be transferred to another ferry.
Eleven of the Penelope crew members refused to sail with the ship. They claim they are owed money by the ferry company.
On Thursday, the Greek Shipowners Association for Passenger Ships (SEEN) and the Panhellenic Seamen's Federation (PNO) signed a new collective labor agreement that means the mariners will not receive any wage increases over the next two years.
PENEN, however, said it does not agree with the deal. Its president, Antonis Dalakogiorgos, said the union would continue its protests against companies that owe employees money.