Of the people rescued, mainly from Africa, some 100 are minors, the MSF charity operating the boat said. Around 40 migrants affected by fuel burns, dehydration, hypothermia and infected scabies have been treated on board.
The Geo Barents took the first migrants on board on June 10 off the Libyan coast. Most of them will now face 14 days of coronavirus quarantine on the 'Aurelia' ship docked nearby.
For years Italy was the primary route into Europe for hundreds of thousands of asylum seekers and other irregular migrants but after a crackdown in Libya against smugglers, the numbers making the perilous journey across the Mediterranean fell.