The country is struggling to accommodate an endless wave of boat migrants, and a crackdown on security at the borders with France and Austria has exacerbated the situation, causing a bottleneck at Italy's train stations.
The crisis "should not be underestimated", Prime Minister Matteo Renzi said, as Austria, France and Switzerland expelled asylum seekers back onto Italian soil.
"Let me be clear, Europe's answers so far have not been good enough," Renzi added.
"Redistributing just 24,000 people is almost a provocation," Renzi said.
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"If Europe chooses solidarity, good. If it doesn't, we have Plan B ready. But it would first and foremost hurt Europe," he said, without providing details.
Renzi has come under pressure to take a stronger stance with the 28-member bloc, with the anti-establishment Five Star movement suggesting Italy threaten to freeze its EU budget contributions if aid is not forthcoming.
Alfano said he would ask the EU at a meeting of interior ministers on Tuesday for "fair distribution of migrants, camps in Libya and a serious policy on repatriation" of economic migrants.
Any such plan for camps would hinge on Libya's opposing factions reaching a political agreement, or Italy convincing the UN to adopt a resolution.
Over 57,000 migrants and asylum seekers have been rescued at sea and brought to Italy so far this year -- up from 54,000 at the same time last year -- Renzi said, and Rome wants both a long-term solution and help from other countries now.