Workers at the Piraeus Port Authority (OLP) and the Thessaloniki Port Authority (OLTH) are due to go on strike to protest privatisation plans on Thursday, prompting fears of a prolonged period of inactivity at the ports.
In 2008, stevedores in Piraeus were involved in a 14-month period of protest action in a bid to prevent the sale of a container terminal to Chinese giant COSCO. It led to OLP losing 55 million euros in revenue.
The port workers are due to begin rolling 48-hour strikes on Thursday. They are also demanding the renewal of their collective contracts.
According to a deal signed in April, COSCO will acquire 51 percent of OLP for 280.5 million euros and the remaining 16 percent for 88 million, after five years once it concludes mandatory investments, which will amount to 350 million euros over the next decade.
The government is expecting bids for a 67 percent stake in OLTH by the beginning of September.
More than 1,100 people are employed at OLP, and another 420 at OLTH.