An urgent rescue operation is being launched to save some of Rome's most important ancient ruins, including the palace where Julius Ceasar once lived, from the ravages of increasingly violent rainstorms that are undermining their foundations.

Archaeologists fear that buildings on the Palatine Hill, most more than 2,000 years old, are becoming dangerously unstable and pose an increasing risk to the 3.5 million tourists who visit the area each year.

Repairs could take up to 10 years, engineers have said, and are expected to cost between €100 and €200 million (£68 and £136 million) - a small price to pay, they say, to preserve some of Rome's historical treasures.

These include the towering Palace of Septimus Severus, the Domus Augustana, where the emperors lived, and traces of an iron-age village where legend has it the city's founders, Romulus and Remus, were once suckled by a wolf.

"We need to do the same as Greece did 30 years ago, with the Acropolis, whose problems were a lot less than ours," said Carlo Giavarini, a conservation engineer at La Sapienza University who is involved in the rescue plan.

"The first thing we have to do at the Palatine is understand how to divert the water that is undermining the walls. The ancient Romans knew how to do it, but not us."

A maze of 2,000-year-old irrigation tunnels runs beneath the hill as part of the complex original plumbing for which the Romans were famed. But they are largely unmapped and have become blocked or have broken in many places. One of the first challenges will be to find ways to dig out these aged drainage systems and link them to new ones serving the half-square-mile area.

Romans were shocked earlier this month when a 15ft section of a wall, one side of a passageway along which visitors walk to the Forum, collapsed. The wall was just 5ft high - lower than most of the structures in the area - and nobody was hurt, but its collapse heightened fears that more serious accidents involving higher buildings could occur.

Although the wall was just 500 years old and may have been put up by the Renaissance equivalent of cowboy builders, engineers discovered extensive damage to its foundations caused by water seepage. There are ominous signs of similar damage to other, older buildings. Angelo Bottini, the archaeological superintendent of the area, said the collapse was "a very loud alarm bell".

Other areas were at risking of falling down, he said, "and this time they could fall on to the crowds of visitors".

Rome has been hit by increasingly violent storms in recent years, thought to be caused by rising temperatures in the Mediterranean. Last week it suffered yet another - ripping trees from the ground and triggering flooding and landslides in the north of the city.

Prof Giampiero Maracchi, a leading climatologist, said: "In general it is raining less, but there has been a change in the intensity of the rainfall. In the past if it rained for a few hours the most you would get deposited would be up to 40 millimetres (1.5ins). Now it is often between 80 and 100 millimetres."

It is not just the risk to visitors behind the drive to restore the buildings, nor even the fact that the site contains some of Rome's most beautiful frescoes: the desire to save the heart of what was once the Roman empire goes to the heart of the Italian psyche.

"Don't tell me that we have to protect these sites only because they draw visitors and make money," said Rocco Buttiglione, the culture minister. "We have to do it because they are part of our soul."

In the first stage of the restoration drive, a team of Italy's foremost archaeological engineers has been set up to conduct a nine-month survey and search for underground weaknesses and fault lines.

"First we have to do the diagnosis, then we have to treat the patient," said Prof Giorgio Croci, the chief engineer on the project, who led the team which stabilised the Basilica of St Francis in Assisi, following the 1997 earthquake.

"We have to go carefully as these remains need to be treated very delicately indeed - but at least the Palatine is finally being treated as a priority."

Prof Croci, who has travelled the globe advising governments on how to protect ancient monuments, added: "Italians are the best in the world at doing this kind of thing, so it is important that we should be also be seen putting our own house in order."