"Seventeen bodies were recovered, 11 people rescued and 47 are still missing," a senior official said on Monday.
The officials said the boat had 75 illegal emigrants - 70 Moroccans and five Tunisians - when it sank off the town of Chott Meriem, 170km southeast of Tunis, a few hours after it left the Tunisian shoreline on Sunday for Italy.
"The 11 rescued are 10 Moroccans and one Tunisian, but we have not identified those who were found dead," an official said, adding that the government had deployed eight ships and an army helicopter to search for the missing.
Efforts stepped up
The North African country's government, eager to maintain good relations with Italy, has stepped up efforts to crack down on illegal emigration from the country's coast.
The authorities have so far this year stopped at least 90 illegal migration attempts to Italy from Tunisia, involving more than 900 people, according to officials and European diplomats.
Italy returned three planeloads
of illegal immigrants on Monday
But rickety boats still leave Tunisia and Libya packed with migrants from Maghreb and sub-Saharan African states escaping poverty and political repression.
They often head to the Italian island of Lampedusa, which is closer to North Africa than to Sicily or mainland Italy.
In a separate development, Italy on Monday sent back three planeloads of illegal immigrants to Libya from Lampedusa. More than 600 migrants reached the tiny island during Saturday night alone.