Heavy rainfall triggered a massive landslide early Saturday on the southern Italian resort island of Ischia, which destroyed buildings and swept parked cars into the sea, leaving at least one person dead and up to 12 missing.

The body of a woman was pulled from the mud, the Naples prefect Claudio Palomba, told a news conference.

With rain continuing to fall, rescuers were working gingerly with small bulldozers to pick through some six to seven metres of mud and detritus in the search for possible victims.

Reinforcements arrived by ferry, including teams of sniffer dogs.

The force of the mud sliding down the mountainside just before dawn was strong enough to send cars and buses on to beaches and into the sea at the port of Casamicciola, on the north end of the island, which lies off Naples.

The island received 126 millimetres of rain in six hours, the heaviest rainfall in 20 years, according to officials.

Streets were impassable and people were urged to stay at home.

At least 100 people were reported stranded without electricity and water, and about 70 were housed in a community gymnasium.

Italy Landslide
Vehicles are covered in mud (Salvatore Laporta/AP)

There was early confusion over the death toll. Vice premier Matteo Salvini initially said that eight people had been confirmed dead, followed by the interior minister saying that no deaths had yet been confirmed, while 10 to 12 were missing.

“The situation is very complicated and very serious because probably some of those people are under the mud,” interior minister Matteo Piantedosi told RAI state TV from an emergency command centre in Rome.

ANSA reported that at least 10 buildings had collapsed. One family with a newborn baby that was previously reported missing was located and was receiving medical care, according to the Naples prefect.

Video from the island showed small bulldozers clearing roads, while residents used hoses to try to get mud out of their homes.

Italy Landslide
Mud covers streets and cars (Alessandro Garofalo/LaPresse/AP)

One man, identified as Benjamin Iacono, told Sky TG24 that mud overwhelmed three adjacent shops that he owns, completely wiping out his stock.

Firefighters and the coast guard were conducting search and rescues, initially hampered by strong winds that prevented helicopters and boats from reaching the island.

The densely populated mountainous island is a popular tourist destination for both its beaches and spas.

A 4.0-magnitude quake on the island in 2017 killed two people, causing significant damage to the towns of Casamicciola and neighbouring Lacco Ameno.