France, Germany and Italy are due to meet in the French capital Paris, to discuss a "coordinated approach" to end Italy's struggle.
The UN refugee agency is mounting pressure on Europe to help Italy defuse the "unfolding tragedy" of tens of thousands migrants flooding its shores.
The move comes as the interior ministers of France, Germany and Italy will meet in Paris on Sunday to discuss a "coordinated approach" to help Italy deal with hordes of migrants and refugees arriving in its ports.
Italy needs more international support to cope with a growing number of migrants who have braved a perilous Mediterranean crossing to reach Europe this year, UN High Commissioner for Refugees Filippo Grandi said on Saturday.
"What is happening in front of our eyes in Italy is an unfolding tragedy.
"Italy is playing its part in receiving those rescued and providing asylum to those in need of protection. These efforts must be continued and strengthened. But this cannot be an Italian problem alone."
Since the beginning of the year, 83,650 migrants and refugees have reached Italy by sea, an increase of nearly 20 percent compared to the same period last year, UN figures show.
Nearly all of Italy's 200,000 places for accommodating migrants and refugees have been filled.
The UN says many refugees and migrants need healthcare and support, with a large percentage being non-accompanied children and victims of sexual violence.
Last week, the country threatened to suddenly stop vessels from other countries disembarking migrants at its ports after rescuing them in the Mediterranean.
"We are confronted with growing numbers that over time could severely test our reception system," Italian Prime Minister Paolo Gentiloni had said.
Speaking in Ottawa, Canada, Italian President Sergio Mattarella warned that "if we continue with these kind of figures, the situation will become unmanageable, even for a large and open country like ours".
Talks in Paris
French Interior Minister Gerard Collomb, German counterpart Thomas de Maiziere and Italy's Marco Minniti are due to meet European Union Commissioner for Refugees Dimitris Avramopoulos in the French capital, Paris on Sunday, a source close to the issue said.
"The aim is to have a coordinated and concerted approach to the influx of migrants in the central Mediterranean," as well as "how best to help the Italians," the source close to the issue said.
German Chancellor Angela Merkel and French President Emmanuel Macron both expressed their backing for Italy on Thursday after a meeting in Berlin.
"Germany will certainly help Italy face this problem," Merkel said.
Macron cited the Italian premier as saying that more than 80 percent of the migrants were seeking a better life economically and were not fleeing war or persecution.