It is the duty of EU member states to help deal with the thousands of migrants pouring across the Mediterranean, the commissioner for migration said.
Dimitris Avramopoulos said that while the EU is developing the policies, the member states and their resources must implement them.
"Europe is accomplishing its duty, it's up to the member states to implement it," he said, referring to a new EU policy to be presented in May.
He urged member states to show solidarity with those bearing the brunt of the arrivals.
His comments come as some 10,000 migrants have been rescued making the perilous crossing to Europe in the past week.
Dozens of migrants have been rescued from a dinghy after their boat's gas cylinder exploded, killing several and injuring others.Read the full story ›
Right-wing parties in Italy have voiced increasing anger at what they call an "invasion" of migrants heading to the country from Africa.
The government in Rome has called for help from regional authorities to provide beds for the thousands of new arrivals - but many politicians have been reluctant to comply.
Among them is Matteo Salvini, head of the Northern League party, who accused the government of running a "taxi service" to help people traffickers. Posting on Facebook, he added:
I ask the League's governors, mayors, assessors and councillors to say no, with every means, to every new arrival. The League is ready to occupy every hotel, hostel, school or barracks intended for the alleged refugees.
Stop the departures and prevent the landings, to save lives.
Head of centre-right party Forza Italia, Giorgia Meloni, has also said the boats setting off from north Africa to Italy "should be stopped as they leave", while Claudio Palomba, the prefect of Rimini, told the Telegraphthat the system was "close to collapse".
Official estimates suggest more than 30,000 people have crossed into Italy and Greece since the start of the year, making the treacherous trip across the Mediterranean to escape from Libya - including 10,000 picked up by search and rescue boats in the last week alone.
At least 900 more are believed to have drowned en route.
The tide of desperate migrants and refugees travelling from Libya to Italy shows no sign of stopping, with more overloaded boats being intercepted by authorities every day.
ITV News Correspondent John Ray reports from Sicily:
Police in Sicily have detained 15 Muslim migrants for allegedly throwing 12 Christians overboard during a fight at sea.
Palermo police learned of the incident while interviewing tearful survivors from Nigeria and Ghana, who arrived on Italian soil yesterday morning, after being rescued at sea.
The survivors said they had boarded a rubber boat April 14 at the Libyan coast with 105 passengers aboard.
During the crossing, Nigerian and Ghanaian Christians claim they were attacked by passengers from the Ivory Coast, Senegal, Mali and Guinea Bissau.
This development is the latest in a growing crisis as Italy struggles to cope with a sudden influx of tens of thousands of refugees escaping instability across Africa.
More than 500 new African migrants have arrived in the Western Sicilian port of Trapani.
The Italian Navy ship Comandante Foscari landed today with 586 arrivals - including women and children.
Italy has admitted it is struggling to cope with the thousands of migrants landing on its shores this spring.
These new arrivals come on the heels of a tragedy earlier this week, in which as many as 400 migrants died during the dangerous crossing between Libya and Italy after their boat capsized.
Another 41 migrants are feared to have drowned in the Mediterranean in another shipwreck, according to the International Organisation for Migrants.
The IOM, an aid agency based in Geneva, said that four survivors reported the disaster when they arrived in the Italian port of Tripani today.
The four migrants were found floating in the sea by a helicopter and were rescued by the Italian Naval ship Foscari. They said left Tripoli in Libya on Saturday, and managed to stay adrift for four days.
Nearly 10,000 migrants have been rescued from boats travelling across the Mediterranean to Italy in the past four days alone, the Italian Coast Guard has revealed.
Since the weekend, thousands of people have tried to make the journey, with official estimates suggesting at least 31,500 migrants have entered Italy and Greece since the start of the year as increasing governmental instability and violence in Africa has prompted a surge in numbers fleeing to Europe.
Another 900 are believed to have drowned on the crossing, including 400 people aboard a boat which capsized on Monday.
The UN has called for a more robust search and rescue mission to be set up in the Mediterranean as it claims the European Union's border protection operation, Triton, is struggling to cope.
A boat carrying hundreds of migrants across the Mediterranean from Libya to Italy capsized when those on board all rushed to one side in a desperate bid to be rescued, an official has said.
Around 400 passengers on board the ship are thought to have died when the ship sank on Monday around 75 miles (120km) from the Italian island of Lampedusa, while 145 were rescued.
Experts say many of those unaccounted for are women and children.
According to testimonies, at least one-third of the passengers were women and children. At the time of the shipwreck, they were staying in the hull of the boat to be better protected from the cold.
When the men on the deck became restless and started moving about because a rescue boat was beginning to approach them, the boat capsized and water flooded the hull. Women and children died immediately.
The United Nations has urged governments across the region to "urgently expand and upgrade search and rescue capacities" in the Mediterranean Sea following the deaths of hundreds of migrants.
In a statement the UNHCR said "the Mediterranean has emerged in recent years as the most dangerous of the world's four major sea routes in use by refugees and migrants" and urged governments to invest in a new "robust rescue-at-sea mechanism."
I am here in Lebanon and we know that Syrians are more and more risking their lives to have access to European territories.
But for all those in need of protection it is very important to increase the number of resettlement opportunities, humanitarian admission opportunities, to have a more flexible visa policy, to have enhanced family reunification programmes, and again I repeat to have an effective mechanism to rescue people at sea in the central Mediterranean.
The UN said that so far in 2015, at least 31,500 people are known to have made crossings to Italy and Greece.
It added that according to the Italian Coast Guard more than 8,500 people have been rescued from several dozen boats and rubber dinghies since April 10th.
About 400 migrants are believed to have died on Monday after a double-decker boat capsized about 120 kilometres south of Lampedusa.