No one is currently allowed to disembark while staff from the Greek public health agency have boarded the ship to perform tests.
Twelve crew members tested positive for the coronavirus after 150 randomized samples were taken, the Greek Coast Guard said on Monday. According to TUI, they were asymptomatic.
But according to Greek media reports on Tuesday, follow-up tests on the same crew members were negative.
The passengers had all been diagnosed in good health after undergoing tests before boarding, according to the spokeswoman for the coast guard.
The cruise ship, the first to return to Greek waters since the lockdown at the end of March, docked in mid-September in the Cretan port of Heraklion and left Sunday evening for the island of Corfu via Piraeus, the port of Athens.
But the ship was stopped and moored off the island of Milos on Monday after suspected cases of COVID-19 were detected, until it was instructed to proceed to the port of Athens.