Greece's privatisation agency had previously set a deadline of July 29 for bids to take a 67% stake in the port. The deadline was moved after one potential bidder requested more time, one of the sources said.

Athens' quest to attract private investment in some of its regional ports as part of a wider plan for privatisations to boost economic growth has been delayed, mainly due to uncertainty linked to the COVID-19 pandemic.

Four investors, including Quintana Infrastructure and Development and a joint venture of Black Summit Financial Group, Euroports, EFA Group and GEK Terna, were shortlisted last year for the Alexandroupolis sale.

Situated in northern Greece, near the borders with Bulgaria and Turkey and with rail links and a floating gas regasification unit in the pipeline, Alexandroupolis has potential as a transport and energy hub for central Europe.

(Reporting by Angeliki Koutantou; Editing by Catherine Evans)