The new measures, which include a scheme to check on the strength of buildings in the area after months of repeated earthquakes, will be discussed at a cabinet meeting later in the day, a government statement said.

Campi Flegrei, or Phlegraean Fields from the Greek word for "burning," lies some 20 kilometers (12.5 miles) from Naples and is dotted with towns and villages, including Pozzuoli, Agnano and Bacoli, which have a combined population of more than 500,000.

The caldera is dotted with 24 craters and is a much bigger volcano than the nearby Vesuvius, which destroyed the ancient Roman city of Pompeii in 79 AD.

It has been jolted by more than 1,100 earthquakes in the last month alone, including a 4.0 trembler on Monday and a 4.2 magnitude quake last week -- the strongest in the area for four decades.

Experts say the increased seismic activity is probably linked to a phenomenon known as bradyseism, when the earth rises, or falls, depending on the cycle, caused by the filling or emptying of underground magma chambers.

There is not an imminent threat of an eruption, most volcanologists say, but with the ground currently rising by 1.5 cm (0.59 inches) a month, there is concern over the impact on local buildings.

Civil Protection Minister Nello Musumeci said this week evacuations would only be triggered in case of "extreme necessity".

The cabinet is also expected to direct more resources to local civil protection agencies to ensure they can swiftly intervene in case of emergency and to fund a communication campaign to raise public awareness, Musumeci said.

Local media reported that a group of hospitals in the area would start evacuation tests from Friday to make sure they are ready to face stronger quakes or eruptions.

The last time Campi Flegrei suffered a comparable burst of earthquakes was in the 1980s. On that occasion, some 40,000 people were temporarily evacuated from nearby Pozzuoli.

The last significant eruption was in 1538. One of its biggest eruptions took place 39,000 years ago and might have led to the extinction of Neanderthal man, researchers say. Magma from that blast has been found in Greenland, some 4,500 km away.

(Reporting by Angelo Amante; Editing by Crispian Balmer and Aurora Ellis)