About 6,055 refugees were rescued on Monday as they tried to reach Europe on 39 boats, one of the highest numbers in a single day, Italy's coastguard said.
The coastguard said nine refugees, including a pregnant woman, had died before the rescue mission had commenced.
Their corpses were found on the vessels.
The coastguard coordinated the rescue of the boats, most of which were overcrowded rubber dinghies in a mission that occurred three years to the day after 366 people died in the sinking at Lampedusa, Italy that first alerted the world to the Mediterranean refugee crisis.
"It is unacceptable that in 2016 these people have no other choice than to embark on these incredibly dangerous sea journeys," said MSF coordinator Nicolas Papachrysostomou.
Two women and a child had to be evacuated for medical treatment after suffering severe burns caused by spilled fuel during a rescue from a rubber dinghy by a boat operated by Doctors without Borders (MSF).
— MSF Sea (@MSF_Sea) October 3, 2016
Just under 200 minors were among those saved from one of the former fishing boats which had some 720 people on board, according to NGO SOS Mediterranee.
Most of the minors were unaccompanied, with nine of them being under five-years-old.
In the disaster three years ago, a fishing boat packed with some 500 people caught fire and sank rapidly in darkness just off the outlying Italian island of Lampedusa in the night of October 2-3, with 366 of those on board dying.
According to the International Organisation for Migration, around 132,000 refugees have arrived in Italy since the start of the year and 3,054 have died in the process of seeking refuge.