Officials said 155 people have been pulled from the waters a half mile from the coast of Lampedusa since Thursday, but as many as 200 are dead, CNN reported Saturday.
A diver who made it to the wreck 150 feet below the surface of the Mediterranean said he saw dozens of bodies inside the boat.
Gusty winds and rough water have prevented divers from recovering the bodies.
Italy declared a day of mourning for the victims Friday and candlelight vigils were held on Lampedusa Friday night.
Italian Prime Minister Enrico Letta announced Friday the victims will be posthumously named Italian citizens, ANSA reported.
He called the shipwreck "a disgrace" and called on other European nations to "raise the level" of intervention with migrants to prevent such incidents from happening again.
Survivors told the U.N. refugee agency the boat's engine stopped as it approached Lampedusa Thursday. Passengers set fire to clothes and blankets hoping to attract help, but the fire spread, causing panic. The boat overturned and sank.
A fisherman who pulled survivors from the water said they were covered in gasoline.