The government will immediately disburse 2 million euros ($2.08 million) as disaster relief for the island, the minister said, adding that the council appointed Simonetta Calcaterra as an extraordinary commissioner.
On Sunday morning, the prefect of Naples, Claudio Palomba, said that the official death toll stood at one, with four people injured and another 11 missing. A total of 167 residents lost their homes.
However, local media reported on Saturday, citing Italy's Infrastructure Minister Matteo Salvini, that eight people died in the disaster.
Rescue efforts continued through the night to clear the rubble and search for the missing.
Ischia Mayor Enzo Ferrandino called the incident a tragedy, according to the SkyTg24 broadcaster. A dangerous situation was also observed in another town, Lacco Ameno, where mudflows destroyed around 10 buildings and trapped roughly 20-30 people in their houses, local broadcaster reported, citing city mayor.
Interior Minister Matteo Piantedosi said that around 200 people were evacuated from the island, adding that the situation was "very serious." Over a hundred firefighters and civil defense officers were working at the scene with 26 units of special equipment and two helicopters deployed.