Nearly 800 people have been rescued from boats in distress in the Mediterranean Sea in the last 48 hours, Italian and Libyan officials said.

The Italian coastguard said on Saturday that it rescued at least 520 people from five boats in Libyan waters late on Thursday, in response to distress signals from the boats headed towards Sicily.

An additional 171 people were also rescued during the overnight mission in the waters north of Tripoli.

The Italian navy's response comes a day after Libya's navy announced it rescued 105 migrants from a boat that broke down off the coast of Garabulli, 50km east of the capital.

This brings the total number of reported rescues over the weekend to 796 people. There were no details on their nationalities.

Greek port authorities also said that they rescued 16 people when a boat carrying mostly Syrian refugees capsized off Mytilene.

In 2013, almost 8,000 people arrived on European shores in the first six months, and 35,000 in the second half of the year. This year, at least 65,000 people took the risk in the first half of the year, and more than 150,000 people have landed since.

The migrants making the perilious journey usually hail from poor or conflict-ridden countries in Africa, the Middle East and South Asia.