Greece on Wednesday registered 262 new COVID-19 infections, the highest figure since the pandemic began and part of a steadily rising trend this month.
The public health organisation also said two more people had died, bringing the total virus death toll to 216.
The number of patients under intensive care has nearly doubled, with 24 reported Wednesday from 13 last week.
Authorities have blamed the spike in infections to the flouting of social distancing rules in restaurants, bars and public gatherings.
Health Minister Vassilis Kikilias said earlier that the average age of those infected in August had dropped to 36 years old.
“It can happen even if you’re young and think you’re invulnerable,” Kikilias tweeted.
The Greek government on Monday announced a night curfew for restaurants and bars in some of its top tourist destinations.
New entry restrictions for Balkan arrivals and flight passengers from several EU countries were also unveiled.
Eateries and bars are closed from midnight to 0700 in a dozen parts of the country, including the popular islands of Mykonos, Santorini, Corfu, Rhodes and Crete.
The cities of Thessaloniki, Larissa, Volos and Katerini are also affected, as is the Halkidiki peninsula which is popular with Balkan visitors.
In addition, all passengers on flights from Belgium, the Czech Republic, the Netherlands, Spain and Sweden arriving from August 17 must provide a negative COVID-19 result obtained up to 72 hours before entry, as must all land border arrivals.
The civil protection agency last week made masks compulsory in all indoor public areas.
Among other measures announced Monday was a decision to scrap Greece’s top trade exhibition, the annual Thessaloniki international fair in September.
The government has ruled out a general lockdown after gradually reopening the economy in May and starting to accept foreign arrivals in June to salvage part of the tourism season which is vital to the economy.
Only 10 percent of cases in Greece can be traced to foreign arrivals.