An Italian warship on Tuesday unloaded the 17 victims and 206 survivors of a migrant boat shipwreck, as Italy threatened to send asylum-seekers across Europe without more help to stem a wave of arrivals from North Africa.

Hearses carrying the 17 coffins could be seen lined up in the port of Catania in Sicily as the Grecale frigate docked and dozens of medical personnel stood by to assist the survivors in four tents set up especially.

"Our society is getting used to this tragic normality. Something needs to change," said Father Piero Galvano, the local director for the Catholic charity Caritas.

Many of the survivors from Monday's accident in international waters between Libya and Italy were from Eritrea, Nigeria and Syria and the victims included 12 women and three children, with more still missing.

Catania's Deputy Mayor Marco Consoli, who was also at the port, said: "We have taken in thousands of people from all around the world, victims of hunger and war."

"Sadly today we are also taking in 17 bodies. If we are usually at 100 percent, today we are at 200," he said.

Survivors will initially be housed in a local sports facility but longer-term shelter will be harder as all the asylum centres in Sicily are badly overcrowded.

Interior Minister Angelino Alfano urged more assistance from Europe for border patrols, threatening that otherwise Italy would defy EU asylum rules and allow migrants to travel on to other countries in Europe.

"We'll just let them go," he said, although the Dublin Convention states that migrants must remain in the country in which they arrive and make their asylum application until their status as refugees is approved.

Alfano also said the EU should intervene in Libya to stop the migrants from leaving in the first place and called for the EU's Frontex border agency to be moved from Poland to Italy to improve coordination.

The ministry reported 36,000 migrants landing so far in 2014 -- many from Eritrea, Somalia and Syria -- compared to 42,925 for all of 2013, 13,267 in 2012 and 63,000 in 2011 at the height of the Arab Spring revolts.

Hundreds, and sometimes thousands, drown every year.

Countries in southern Europe complain they are shouldering the burden of migrant arrivals but northern European states take in more confirmed refugees, while the EU's border agency Frontex is stretched thin.

"Europe is leaving us on our own," Prime Minister Matteo Renzi, who has promised to make immigration a top priority during Italy's EU presidency this year, said on ReteQuattro television after Monday's disaster.

"It can't save governments and banks and then let mothers and children die," the prime minister said.

- 'Strengthened' search and rescue -

The Italian navy said the rescue operation after Monday's incident had involved warships, coast guard and border patrol vessels as well as merchant ships.

The UN's refugee agency estimated 170 people have died at sea trying to reach Europe this year off Greece, Italy and Libya as well as in international waters.

UNHCR said search and rescue operations should be "further strengthened" and asked for the international community to find legal alternatives like resettlement to stop refugees from making dangerous journeys.

Italian media cited coast guards as saying that around 400 asylum-seekers may have been on board the boat, which would leave dozens still unaccounted for.

But Mauro Casinghini, the director of rescue services in Italy for the Order of Malta, which had a doctor and two nurses assisting survivors with the coast guard at the scene, said there were some 250 people on the boat.

Casinghini described to AFP scenes from the shipwreck as recounted to him by the doctor, Antonella Godino.

A Somali woman, Amina, was found gripping a piece of wood floating in the water and holding on to her four-month old baby after the boat capsized and sank in international waters between Libya and Italy.

"She nearly didn't make it. The waves were lapping at her chin and she was barely holding her baby above the water," he cited Godino as saying.

"When we held the little baby, we were afraid his heartbeat would not come back. We dried him, wrapped him up in a thermal blanket and put him in the warmest place we could find -- next to the engine room."

The Italian navy launched a large-scale operation to rescue migrants and deter traffickers following two separate shipwreck tragedies in October 2013 in which more than 400 people drowned off Italy's shores.