All of Italy became a mask-free, "low-risk" zone for coronavirus Monday, marking a dramatic milestone for the first European country to be hit by the global pandemic in February 2020.

In a decree that took effect Monday, the health ministry for the first time classified each of Italy's 20 regions as "white", signifying low risk, under the country's colour-coded classification system that evaluates Covid-19 risk.

That means facemasks will no longer be compulsory in outdoor areas -- welcome news across the country where an ongoing heatwave is expected to push temperatures past 40 degrees Celsius (104 degrees Fahrenheit) in some southern areas this week.

Once a symbol of the coronavirus crisis in the West -- where images of army trucks transporting coffins from the overflowing morgue in the northern city of Bergamo were seen around the world -- Italy has seen Covid-19 infections and deaths plummet in recent weeks.

A third of Italy's population over the age of 12 has been vaccinated as of Sunday, or 17,572,505 people, according to the government.

Long prohibited from entering the country, tourists from the European Union, Britain, the United States, Canada and Japan are now back after the government removed a quarantine requirement for vaccinated visitors, or those who test negative.

Despite the progress, Health Minister Roberto Speranza urged Italians to be vigilant.

"It's an encouraging result, but caution and prudence is still needed, especially because of the new variants," Speranza wrote, after signing the ordinance Saturday. "The battle is not yet won."

After a long period beginning in November of full or partial regional lockdowns to combat a second wave of coronavirus infections, restrictions were relaxed all over Italy late last month. The entire country was made a "yellow zone", which brought more freedoms but maintained an overnight curfew that shortened restaurant hours.

As the government gradually eliminated the restrictions over the course of June, the lone holdout, until Monday, was the Aosta Valley, the small alpine region in the northwest.

In Italy, more 127,000 people have died of Covid-19-related complications, while more than four million people have been infected.