TUNIS: At least 11 migrants have died in a shipwreck off Tunisia's coast and 44 others are missing, judicial sources said Monday, revising an earlier toll of four fatalities.

"Seven new bodies have been recovered on Sunday evening," said Faouzi Masmoudi, spokesman for the court in Sfax, Tunisia's second city near the site of the sinking that took place over the weekend in the Mediterranean Sea.

Two have been rescued out of the 57 people aboard the boat, all from sub-Saharan African countries, Masmoudi said, adding that the authorities were searching for the missing migrants.

The North African country has become a major gateway for irregular migrants and asylum seekers primarily from other parts of the continent, attempting perilous voyages in often rickety boats in the hopes of a better life.

Survivors of the latest reported sinking, near Tunisia's Kerkennah Islands in the Mediterranean Sea, said the makeshift boat had departed over the weekend from a beach north of the coastal city of Sfax with 57 migrants on board.

According to Tunisia's interior ministry, 901 bodies had been recovered this year by July 20 following maritime accidents in the Mediterranean, while 34,290 migrants had been rescued or intercepted. 

Most of them came from sub-Saharan African countries, it said.

Nearly 90,000 migrants have arrived in Italy this year, according to UN refugee agency UNHCR, with most of them having embarked from Tunisia or neighbouring Libya.

The central Mediterranean migrant crossing from North Africa to Europe is the world's deadliest with more than 20,000 fatalities since 2014, according to the International Organization for Migration.

Crossing attempts have multiplied in March and April following a incendiary speech by President Kais Saied who had alleged that "hordes" of sub-Saharan migrants were causing crime and posing a demographic threat to the mainly Arab country.

Xenophobic attacks targeting black African migrants and students have increased across the country since Saied's February remarks, and many migrants have lost jobs and housing.

Since early July, hundreds of migrants have been driven out of Sfax after a Tunisian man's death in an altercation with migrants.

During the following days, Tunisian police have taken migrants to the desert or perilous areas near the Libyan and Algerian borders, rights groups and international organisations said.

Humanitarian sources have put their number at over 2,000, with at least 25 reported deaths of migrants abandoned in the Tunisian-Libyan border area since last month.

The distance between Sfax and Italy's Lampedusa island is only about 130 kilometres (80 miles).

At least 30 migrants are missing after two unrelated sinkings near the Italian island of boats that departed last week from Sfax, according to survivor testimony.