OLP (OLPr.AT: Quote, Profile, Research, Stock Buzz), which made a net profit of 12.3 million euros in the same period last year, said sales fell 43.2 percent year-on-year, with business at the port's container terminal seeing the sharpest decline.
"Due to the dockers' refusal to work overtime and weekends for the second consecutive quarter, cargo business has been reduced with income at significantly low levels," the company said in a bourse filing.
OLP has seen containers pile up as dockers have refused to work overtime since January in protest at the government's planned privatisation of the port's container business.
China's Cosco Pacific (1199.HK: Quote, Profile, Research, Stock Buzz) won a tender in June to run and update OLP's port facilities for up to 35 years, and is scheduled to sign the contract by the end of 2008.
OLP shares have lost about 13 percent since the start of the year, outperforming the Athens stock market general index , which is down about 37 percent.
Its shares trade at about 20 times estimated 2008 earnings, compared with a multiple of about 13 for the pan-European sector of Marine Ports, according to Reuters Estimates.