ROME, Italy - Italy has reintroduced the mandatory wearing of face masks in outdoor spaces to contain mounting coronavirus cases driven by the Omicron variant, Health Minister Roberto Speranza said Thursday.

The minister, who announced the measure to the cabinet, did not say when the rule would come into effect but stated that higher quality masks would be required in certain venues including cinemas, theatres, sporting events and on public transport.

"It's a difficult phase" in the face of raging infections that the country is confronting because of the Omicron variant of coronavirus, Speranza said.

New measures "should create stronger protections for our population and our health system," he added.

The government also decided to reduce the validity of health certificates issued to those who have received vaccinations from nine months to six starting from February 1.

People will be able to access booster jabs four months after their most recent dose, down from six months, with the new rule to be introduced at an unspecified future point.

New Year's celebrations are effectively forbidden in Italy as all mass gatherings, parties and events are banned until the end of January -- even outdoors.

Nightclubs and similar venues will also remain closed until January 31.