In just 48 hours, 4,000 immigrants have made it by boat to Italian shores.
The arrivals from Africa and the Middle East are the highest number since Italy launched a naval operation two years ago to handle the influx.
Italy said it had rescued around 2,500 of the 4,000 arrivals and that others were being intercepted by merchant ships and coastguard vessels.
"The landings are non-stop and the emergency is increasingly glaring," the interior minister, Angelino Alfano, said.
"Right now two merchant ships are rescuing two boats with 300 and 361 people aboard. It appears there's at least one corpse on board." Alfano estimated that 15,000 migrants crossing the Mediterranean had been rescued so far this year.
He claims up to 600,000 people from Africa and the Middle East are ready to set off from Libyan shores.
"There are death merchants who profit from this people-trafficking and who send out requests for help just 30 to 40 miles after leaving the Libyan coasts."
He called upon the EU to help, saying that the EU’s contribution of €80 million to its border control agency has not resolved the problem.
Italy reported a 60% increase in asylum claims last year – mainly people fleeing the war in Syria – although numbers of arrivals are still lower than after the Arab Spring revolts in 2011.
More than 400 migrants from Eritrea and Syria died in twin tragedies on the Italian coast in October 2013. Since then naval ships have been scouting the region south of the small island of Lampedusa which lies close to Libya.
