UNHCR, the UN's refugee agency, called it "the worst Mediterranean tragedy" so far this year.
Around 150 African migrants died off the Libyan coast on Thursday, in their apparent bid to reach Europe.
Now their bodies are washing up on nearby beaches.
The Libyan Red Crescent recovered more than 60 bodies on Friday and the country's coastguard has retrieved dozens more.
"There were 300 of us in the boat and then water came in," said one of the survivors, Eritrean Abdallah Ahmed Abdallah, in a television interview. "One hundred people were rescued but the rest all died. The women, children and girls all died. Glory to God, we started swimming for almost seven hours and then we were rescued by fishermen."
The Libyan Red Crescent said the wooden boat sank north of the coastal city of Khoms. It had been carrying up to 350 migrants, mostly from Eritrea, Egypt, Sudan and Libya.
Abdallah and the other survivors remain in a desperate predicament, still stuck in a dangerous and conflict-haunted country.
On Friday UNHCR said 84 survivors were taken to Tajoura detention centre.
It lies near the frontline of Libya's deadly civil war where at least 50 people were killed and more than 100 wounded by an airstrike at the beginning of this month.
It's not clear if Abdallah was taken to Tajoura detention centre after he talked to the TV crew. Earlier, when they interviewed him, his group were resting in the shade in a dirty, litter-strewn compound of empty, neglected buildings.
"We have been here for two days and no one has come to get us. There has been a dead body here with us for the past two days," he said, gesturing to where it lay.
"Glory to God, it is like we were fighting death in the sea, and now we are fighting death on the ground."