Over 1000 immigrants arrived in Italy within the last few hours while hundreds of others, rescued by humanitarian vessels, were waiting for a port to receive them, NGOs and Italian authorities said Sunday.

More than 600 people attempting to cross the Mediterranean on board a drifting fishing vessel were rescued on Saturday by a merchant vessel and coastguards off Calabria, at the southern tip of Italy. They were landed in several ports in Sicily.

Italian authorities also recovered five bodies of immigrants who died in undetermined circumstances.

On the island of Lampedusa, some 522 people from Afghanistan, Pakistan, Sudan, Ethiopia and Somalia, among others, arrived from the late hours of Saturday in 15 different boats from Tunisia and Libya.

According to the Italian media, the island's reception centre has been overwhelmed.

With a capacity of 250-300 people, it currently hosts 1200, Ansa news agency said.

According to La Sicilia daily, the latest arrivals on Lampedusa came both by ships carrying dozens, even hundreds of people, as well as by small inflatable boats.

Four Tunisians, including one woman, ran aground during the night on the beach of Cala Pisana after crossing the stretch of sea separating Tunisia and the Italian island, the daily said.

Offshore NGOs continued to recover hundreds of migrants in distress in the Mediterranean. SeaWatch reported that it had carried out four rescue operations on Saturday.

"On board SeaWatch3, we have 428 people, including women and children, a woman nine months pregnant and a patient with severe burns," SeaWatch said on its Twitter account.

OceanViking, operated by non-governmental organisation SOS Mediterranean, reported that it had recovered 87 people, including 57 unaccompanied minors, who were crammed onto "an overcrowded inflatable boat in distress in international waters off Libya".

Between 1 January and 22 July, 34,000 people arrived in Italy by sea compared with 25,500 during the same period in 2021 and 10,900 in 2020, Italy's Interior Ministry said.

International Organization for Migration estimates that 990 people have died and disappeared since the beginning of the year. It says the Central Mediterranean migration route is the most dangerous in the world.