Italy's health ministry announced the latest changes to the tiered system of coronavirus rules in a press conference on Friday evening.

The red-zone regions of Campania, Tuscany, Valle D'Aosta and the autonomous province of Bolzano will become orange zones.

Orange zones Emilia Romagna, Friuli Venezia Giulia, Marche, Puglia and Umbria will turn yellow.

Italian health minister Roberto Speranza will sign an ordinance on Friday night, and the changes will come into effect from Sunday December 6th.

The ordinance will also renew the current measures in Abruzzo, Basilicata, Calabria, Lombardy and Piedmont. 

The classificatons are made based on the coronavirus situaton locally according to a weekly analysis of each region's weekly health data by the health ministry together with the Higher Health Institure (ISS).

People in the highest-risk zones are told to stay within their comune, or municipality, and are only allowed to leave for work, study, health or other essential reasons.

EXPLAINED: How Italy decides which regions are Covid-19 red zones

GRAPHS: Track the spread of coronavirus in every region of Italy

ANALYSIS: Has Italy's coronavirus second wave peaked?

This week, the data showed a another decrease in the incidence of Covid cases overall nationwide over the last 14 days.

These data “are encouraging and confirm the effects of the (government's anti-coronavirus) measures,” the ISS weekly monitoring report stated, however it noted that “the pressure on hospital services is still very high”.

On December 1st, 18 regions reported having exceeded critical thresholds in hospitals or intensive care units, the report said.

“In five weeks we went from a very worrying Rt number of 1.7 to a figure of 0.91,” Health Minister Roberto Speranza told Italian newspaper Il Sole 24 Ore on Friday evening. “This does not mean a narrow escape, but it means that the measures have produced effects.”

“The objective of the government and the regions was to go below 1, we finally succeeded, but there is still a very difficult game in progress”.

The announcement of the latest changes to the tier system came a day after the government announced a new set of restrictions under the latest emergency decree, which is in force from December 4th to January 15th.

It included further travel restrictions throughout December, as the government aims to discourage trips, gatherings and parties over the festive period.

TIMELINE: How Italy's coronavirus rules get stricter towards Christmas

Under its latest emergency decree, the Italian government will require EU citizens to take a coronavirus test before travelling to Italy between December 10th-20th.

From December 21st everyone arriving in Italy during the Christmas period from overseas, including returning citizens and residents, to quarantine for 14 days.

The government also announced a ban on travel between regions over Christmas, and a ban on moving between towns on December 25th and 26th and January 1st.

These rules will apply nationwide, regardless of an area's classification under the tiered system.

Find all of The Local's latest coronavirus updates here.