The latest shipwreck is the most deadly in the Mediterranean since February 2 when 90 people drowned off the coast of Libya
More than 50 migrants drowned in the Mediterranean on Sunday, the majority off the coasts of Tunisia and Turkey, while Italy marked a sea change in its policy.
Tunisian authorities said 48 bodies were recovered off the country's southern coast, close to the city of Sfax, while 68 people were rescued.
"The boat had a maximum capacity of 75 to 90 people, but there were more than 180 of us," said Wael Ferjani, a Tunisian survivor from the southern region of Gabes.
While water leaked into the boat, some passengers jumped into the sea and drowned, he told AFP.
The latest death toll was published around 1800 GMT, after the search and rescue operation had ended for the day.
The hunt for survivors would continue on Monday morning, Mohammed Salah Sagaama from Sfax's naval base told AFP.
Tunisians and migrants regularly try to cross the Mediterranean to seek a better future in Europe, with 120 mainly Tunisians rescued by their navy in March after trying to reach Italy.
In October, a collision between a migrant boat and a Tunisian military ship left at least 44 dead, in what Prime Minister Youssef Chahed called a "national disaster."
The latest shipwreck is the most deadly in the Mediterranean since February 2 when 90 people drowned off the coast of Libya, according to the IOM.
Across the Mediterranean, nine Syrians including seven children drowned when their vessel sank off the coast of Turkey.
The group were travelling in a speedboat intending to head illegally to Europe, when the boat hit trouble off the coast of the southern Antalya province, state media reports said.
The oldest child to drown was 14 and the youngest just three, according to the Anadolu news agency.
Six adults were reportedly rescued including a couple who lost five of their children in the disaster.
Turkey was the main sea route for migrants to Europe in 2015, when more than a million people crossed to Greece.
That year 3,771 people were recorded as dead or missing in the Mediterranean by the United Nations refugee agency.
So far this year, 32,601 migrants and refugees have survived the sea crossing and 649 have been recorded as dead or missing.
A deal struck with the EU in 2016 has drastically reduced the amount of people trying to make the sea crossing, although observers say the numbers have been ticking up again in recent months.