The migrant rescue ship Ocean Viking rescued 86 people off the coast of Libya on Tuesday as their vessel foundered while trying to reach Europe, its French-based operator said.
"The rescued, mainly from Gambia and Senegal, were suffering from dehydration, exhaustion and fuel burns," a spokesman for the charity told AFP.
He added that most of the migrants were minors, trying to cross the Mediterranean on their own, without family.
Italian authorities have said the passengers can disembark at its port of Bari, which the charity said was still a three-day voyage away.
According to the Italian interior ministry, around 90,000 migrants have arrived by sea so far this year.
The UN's International Organization for Migration estimates that 1,724 migrants had disappeared trying to cross the Mediterranean to Europe so far this year, up from 1,417 last year.