ATHENS — With Greece's New Democracy government eager to get tourism restarted with the winding down of a COVID-19 Coronavirus lockdown, health officials are worried some arrivals could bring a resurgence of the disease.

After initially limiting the first wave to 29 countries with similar records of holding down the number of cases and fatalities, tourism was opened to all with the need fto get the economy going again.

Most businesses were shut down for two months or more during the lockdown and the international airport closed almost all traffic but the government said some tourism will begin June 15 and a full start on July 1 with the opening of seasonal hotels.

Manolis Dermitzakis, a Professor of Genetics at the Medical School of the University of Geneva, told SKAI TV that if 6-10 million come – far smaller than 2019's record of 33 million – that there could be 6000-10,000 who come without showing symptoms and won't be tested before leaving their countries or landing in Greece but carry the virus.

The government said there will be random testing and that those coming from the hardest-hit countries, such as the United Kingdom, will be checked and put into quarantine for up to 14 days if proved positive, a likely deterrent for coming.

Dermitzakis said even the virus reappears through tourists that it will be manageable as the government's quick lockdown held down the number of cases and deaths and allowed time to re-gear hospitals savaged by austerity-driven budget cuts.

A report by Greece’s National Public Health Organization showing a startling 36% rise in imported COVID-19 cases in 10 days up to June 6, nearly twice as many as the country recorded in total from the start of the pandemic has set off alarms.

Greece's tourism re-launch will proceed as planned on June 15, when the first wave of travelers is due to fly in from 29 countries deemed safe but as Dermitzakis there will be cases among them.

With the gradual lifting the lockdown starting on May 4 with more weekly openings, Greeks are ignoring social distancing advice to stay at least 1.5 meters (4.92 feet) apart and crowding in public gatherings, which could be breeding grounds for the virus.

After a dozen passengers on a Qatar Airways flight from Doha that landed in Greece tested positive for COVID-19 and were put into quarantine, worry rose that with tourism restarting June 15 that visitors will bring a resurgence of the virus.

A full reopening of tourism is slated for July 1 although it's uncertain whether international air traffic will pick up in full force or how many people will be willing to travel after the gradual opening of lockdowns aimed at preventing the virus' spread.

“The one word we keep hearing in the meeting rooms, offices and hallways of EODY is ‘arrivals.’ Given that circulation of the virus has almost stopped in the local community, this is what can change the picture in the country,” Georgios Panagiotakopoulos, an infectious disease expert from the University of Patra, told Kathimerini.

Until June 15, all passengers arriving from abroad will be tested for the virus and quarantined for 14 days at specially designated hotels if they test positive, the following two weeks ending June 30 a critical test period.

Testing will be mandatory for all arrivals from countries that are not on the “safe” list of the European Union Aviation Safety Agency (EASA) until the end of the month and if all goes well, only random spot checks will be conducted as of July 1, the report said.

Tourism is the catalyst, a sector that in 2019 saw 34 million people bringing in some 19 billion euros ($20.9 billion) in revenues but with fears the numbers could fall as much as 70 percent this year with people afraid to travel even after lockdowns end.

The industry employs 850,000 workers with the government pumping in 17.5 billion euros ($19.25 billion) in 800-euro ($880.08) in benefits to workers laid off during the lockdown and businesses subsidized to keep them from going under.

“But tourists will only travel to Greece if they feel it’s safe. Safety must include social distancing, effective and immediate treatment of those who become sick, and contact tracing,” said Greek heritage analysts for Fortune magazine, William J. Antholis and Filippos Letsas.