More than 40 migrants, including a baby, have died and dozens more have survived after their overloaded boat sank in rough seas off southern Italy.

The vessel reportedly broke apart while trying to land with more than 100 people aboard near the coastal town of Crotone in the Calabria region.

Many bodies have been recovered from the beach at a nearby seaside resort.

Large numbers of people fleeing conflict and poverty make the crossing from Africa to Italy each year.

"At the current time, 80 people have been recovered alive, including some who managed to reach the shore after the sinking," the coastguard said in a statement.

"Forty-three bodies have been found along the coastline," it added.

It is unclear where this boat had travelled from but local news agencies are reporting that those aboard were from Iran, Iraq, Syria, Afghanistan, Pakistan and Somalia.

The vessel sank after it crashed against rocks during rough weather, the Adnkronos news agency said.

The Italian authorities have mounted a large search-and-rescue operation on land and at sea.

Video footage shows timber from the wreckage that has been smashed into pieces washing up along the beach, along with parts of the hull.

Survivors are seen huddled under blankets, attended to by Red Cross workers. Some have been taken to hospital.

"There had been landings but never a tragedy like this," the mayor of Cruto, Antonio Ceraso, has told Rai News.

Italian Prime Minister Giorgia Meloni - elected last year partly on a pledge to stem the flow of migrants into Italy - expressed "deep sorrow" for the incident, blaming the deaths on traffickers.

"It is inhumane to exchange the lives of men, women and children for the price of the 'ticket' they paid in the false perspective of a safe journey," she said in a statement.

"The government is committed to preventing departures, and with them the unfolding of these tragedies, and will continue to do so."

Ms Meloni's right-wing government has vowed to stop migrants reaching Italy's shores and in the last few days pushed through a tough new law tightening the rules on rescues.

According to monitoring groups, more than 20,000 people have died or gone missing at sea in the central Mediterranean since 2014.

Pope Francis, who often defends the rights of migrants, has said he is praying for the dead, the missing and those who survived.