A Chinese man is being treated at the capital’s Attikon Hospital on suspicion of being a coronavirus carrier.
The 33-year-old began showing symptoms pointing to coronavirus after travelling from China to Greece.
He will remain quarantined at the hospital until final results are received.
So far, there have been no cases of coronavirus infections in Greece.
The flu-like virus has killed more than 1,100 people worldwide, all but two in mainland China.
On Wednesday, China reported its lowest number of new coronavirus cases since late January.
Franco-British biotech company Novacyt said on Tuesday it had designed a test able to detect the coronavirus in less than two hours.