Thirteen women were confirmed dead on Monday and ‘at least 15’ were reported missing at sea following a migrant shipwreck overnight off the Italian island of Lampedusa.

‘For the moment 13 corpses (all women coming from Western Africa) have been recovered, and at least 15 migrants are still missing,’ tweeted a UN migration agency spokesman, Flavio Di Giacomo.

Earlier, an Italian coastguard statement said 22 survivors were rescued after a vessel carrying about 50 people capsized some 11 kilometres off Lampedusa's shores.

Di Giacomo, who works for the International Organization for Migration (IOM), told dpa that Tunisians and sub-Saharan Africans from Ivory Coast, Burkina Faso and Guinea were on the boat.

It overturned in rough sea conditions shortly after midnight (2200 GMT) because migrants rushed to one side as two Italian rescue units approached it, the coastguard said.

Salvatore Vella, a Sicilian prosecutor investigating the accident, told reporters that the boat had set off from Libya and made a stop in Tunisia before heading north.

He added that nobody aboard had life jackets. ‘If they had, they would all be safe now,’ Vella said in comments carried by the ANSA news agency.

Children, including babies, are among the missing, Vella said. ANSA quoted a survivor as saying that her sister and her 8-month-old niece were unaccounted for.

The Ocean Viking charity vessel, operated by Doctors Without Borders (MSF) and SOS Mediterranee, and units coordinated by the EU border agency Frontex were taking part in the search for the missing.

Another charity, Spain's Open Arms, rescued 40 people in another overnight operation. ‘One child and a baby among them. We found them in a wooden shell and took them to the #OpenArms,’ it tweeted.

Lampedusa, a small island that is roughly halfway between Sicily and Tunisia, is often the first port of call for Europe-bound migrants from North Africa.

According to the IOM, 660 people have died or gone missing since the start of the year on the sea route between Tunisia and Libya on the one side, and Italy and Malta on the other.

Monday's shipwreck took place on the eve of EU talks in Luxembourg in which the bloc's interior ministers are due to discuss an EU-wide relocation mechanism for incoming sea migrants.

The mechanism is meant to end the bitter intra-EU disputes that have roiled the bloc over the past few months on who should take in sea migrants.

During those disputes, migrants rescued by charity vessels were left waiting at sea for days and weeks because Italy and Malta refused to take them in until other EU nations also agreed to take some of them.