Five people were still missing on the island of Ischia on Sunday after a landslide triggered by torrential rain ripped through the southern Italian holiday destination. At least seven people, including a newborn baby and two children, were killed.

Naples prefect Claudio Palomba held a news conference on Sunday while dozens of emergency workers continued to search the island and its waters off the coast.

Torrential rain triggered a wave of mud, debris and stones to break away from the island's highest mountain on Saturday, which crashed down over houses and roads in and around the port town of Casamicciola Terme.

Many buildings were smashed by the landslide and several cars pushed into the sea by what one resident described as "a waterfall of water and mud."

The densely populated island, some 30 km (19 miles) off the coast of Naples, has long drawn visitors to its thermal baths and picturesque coastline.

However, experts say episodes of heavy rainfall such as Saturday's are becoming more common and more intense due to the intensified effects of climate change, making hydrogeological risks worse in many parts of Italy.

Statistics show Ischia has a large number of houses that were built illegally, putting inhabitants at permanent risk from flooding and earthquakes.

"It is the fault of our old politicians, who did not do preventive work on the mountains," said Ciro Buono, a 72 year-old-Ischia resident.  

"They cut down the trees, and this is the consequence. It had already happened in 2010 when a 15-year-old girl died. This time it was a catastrophe."

The fatal landslide has reignited anger over pardons for illegal buildings granted in recent decades and allegations that politicians continue to fail to address the issue.

"People must understand that they can't live in some areas and buildings in risky areas must be torn down," Campania governor Vincenzo De Luca told state broadcaster RAI on Sunday.

Italy's new far-right government led by Giorgia Meloni held a cabinet meeting on Sunday and issued a decree aimed at providing aid following the disaster, including to some 230 people who were evacuated.

An initial amount of 2 million euros ($2.08 million) has been set aside, with plans to suspend tax payments for island residents until the end of the year.

Part of a wider issue in Italy, the head of the national civil protection agency said on Monday that more than 90 percent of Italian municipalities were prone to landslides or other natural disasters. 

"94 percent of municipalities are at risk of flooding, landslides, coastal erosion," Fabrizio Curcio told La Stampa newspaper, adding that "all of Italy is at risk."

He added that Ischia was at greater risk because many of its houses were built illegally. 

However, he stressed that other parts of Italy with fewer land planning violations were also vulnerable.