The "ultimate objective" of Celestyal was new builds, and the line was working with a ship designer to achieve its aim.
"We don't want to get into big vessels, the maximum size we are looking at would be 1,800 passengers and around 60,000 tons."
He added that both ships would be specially designed for 3-or 4-day itineraries, with all outside cabins with balconies.
Celestyal Cruises currently operates three ships - Celestyal Olympia, Celestyal Crystal and Celestyal Nefeli. It will take delivery of two more - Thomson Majesty and Thomson Spirit - in November 2017.
Ahead of any new builds, Mr Anastassiadis confirmed the line would base Celestyal Olympia in the Gulf from November 2017. The 1,664-passenger ship will be based in Dubai and offer 3- and 4-night cruises taking in Muscat (Oman), Doha (Qatar) and Mina Salman (Bahrain) until April 2018.
Earlier this year, the line confirmed that Celestyal Crystal would be based in Cuba year-round from this November - and could be joined by a fleetmate from November 2017.
A second ship in Havana would likely offer 3- or 4-day itineraries, in keeping with the line's successful Aegean cruise model.
The 1,462 Thomson Majesty will be deployed in Western Mediterranean to visit smaller ports.