Three of the boats with 260 people on board were intercepted by Italian coast guards and taken to an immigration centre on the tiny island of Lampedusa, which is closer to north Africa than to the Italian mainland.
Maltese armed forces rescued a dinghy packed with 82 migrants 68 nautical miles south of the island.
The migrants, who said they were from Somalia, had sent out a distress signal when the dinghy’s engine failed.
The group included 10 women, one of whom is pregnant, and a toddler.
Tens of thousands of migrants have arrived on Italian shores since the Tunisian revolution in January 2011 set off a chain reaction across north Africa, bringing tumultuous political change and severe economic hardship.