The incident occurred on Libya's western coast, according to pan-European maritime rescue humanitarian organisation SOS Mediterranee.
ADVERTISEMENTAn aid group that rescues migrants stranded in the Mediterranean has said one of their missions was interrupted by armed bandits.
The raiders boarded the overloaded boat and sped away after the migrants threw themselves into the sea for safety.
According to video footage posted by SOS Mediterranee volunteers were helping 93 passengers from an overcrowded wooden boat onto the rescue vessel when the bandits approached in rubber dinghies.
The hijackers climbed onto the boat where the migrants were crowded as the rescuers carried on evacuating them.
After throwing themselves into the water for safety 15 of them were recovered by the NGO as the bandits drove away with the boat.
SOS Mediterranee reported that one man collapsed as a result of hypothermia and stress following the incident.
It wasn't immediately clear what the bandits motivation for taking the boat was. Often, boats are intentionally sunk by Italian maritime authorities for safety.
Valeria Taurino, general director of SOS Mediterranee, said in a statement that, "the lack of rescue vessels left by states in recent years in the central Mediterranean has generated a reckless increase in armed presence and illegal and dangerous actions for both the fleeing shipwrecked people and aid workers."
The rescue was one of several this week however overall levels of migrants arriving in Italy by boat have halved from this time last year according to the Italian Interior Ministry.
Italy's Prime Minister Giorgia Meloni has made tackling migration a priority, signing deals with African countries to block departures, limiting the work of rescuers and targeting traffickers.