SCORES of people were missing at sea overnight after a tiny boat carrying more than 200 African migrants fleeing Libya capsized off the coast of Italy in three-metre-high waves.

The Italian coast guard said 50 survivors had been rescued and a helicopter crew aiding the high-seas rescue operation had spotted about 20 bodies near the boat.

"We are still hoping. Our boats and helicopters have thrown all sorts of life jackets and lifeboats to allow people to hold on," coast guard spokesman Vittorio Alessandro told AFP from the southern Italian island of Lampedusa.

Around 130 people who were on the 13-metre boat are believed to be missing, while a fishing boat in the area rescued three more survivors.

The island state of Malta said it was helping to coordinate rescue efforts.

Helicopter pilots quoted by Italian news agency ANSA said they had seen "dozens" of corpses in the area including those of small children.

"We hoped one of them would raise their arm. But no one did," one said.

Italian Prime Minister Silvio Berlusconi told reporters he would be visiting the island on Saturday and sent his condolences to victims' relatives.

"The Government and I are personally following the tragedy with sorrow and emotion," he said. "We are talking about desperate people, who had faced the dangers of the crossing in order to reach our coasts and better their lives."

Shaken-looking survivors wrapped in thermal blankets were helped off a coast guard boat on Lampedusa. Some, including a pregnant woman, were immediately taken to hospital in ambulances.

"The bad weather started at about six pm yesterday... Our boat broke apart. We fell into the water. It was hell. There was water in my mouth but I managed to stay afloat," said 29-year-old Peter Ugo, from Cameroon.

The International Organisation for Migration , based in Geneva, said it estimated some 300 people were on the boat which capsized and sank in the early hours of the morning.

"The survivors are all in a state of shock. One man told me he had lost his one-year-old son. One of the two surviving women told me how she had lost her husband," said the IOM's Simona Moscarelli, who is in Lampedusa.

The coast guard said in a statement that the boat had departed two days ago from the town of Zuwarah in western Libya near the border with Tunisia. The statement said the people on the boat were mostly Eritreans and Somalis.

Hundreds of African refugees from Libya - many of them migrant workers stranded after the start of an uprising against Libyan leader Moammar Gaddafi and the beginnings of a civil war - have landed in Italy in recent days.

Angelina Jolie , Goodwill Ambassador for the United Nations' Refugee Agency (UNHCR), who had just returned from a humanitarian mission in Tunisia, said she was "greatly saddened."

"We have to urgently find solutions to guarantee a safe corridor to civilians fleeing the fighting in Libya," she said, according to a UNHCR statement that quoted her in Italian translation.

More than 20,000 migrants fleeing continuing unrest in Tunisia have also arrived on Lampedusa in recent weeks, sparking a humanitarian emergency.