Two commercial ships and an Italian coastguard vessel rescued about 700 migrants from overcrowded boats near the Libyan coast today, days after more than 300 people died trying to make the crossing to Europe.

Rome's coastguard command centre organised rescue operations, which started early this morning after it received a distress call by satellite phone, a coastguard spokesman said.

"All of those rescued appear to be in good shape and the sea conditions are good and getting better," the spokesman said.

More than 300 migrants died trying to reach Italy from North Africa in stormy seas this week. Italy shut down its Mare Nostrum search-and-rescue operation last October and it has been replaced by a more limited EU border control mission, Triton.

The weather has improved since the beginning of the week, the coastguard said, opening the way for migrant boats to set off again from Libya, where the breakdown in law and order has allowed people-smugglers free rein.

The UN refugee organisation UNHCR says at least 218,000 migrants crossed the Mediterranean by boat last year and 3,500 lives were lost.

This week's deaths have renewed focus on the European Union mission. Unlike its predecessor, Triton does not have a specific search-and-rescue mandate, and limits its border control operations to the waters near the Italian coast.