"The situation is as simple as it is tragic: We received no emergency signals from Frontex," the European border and coast guard agency, Meloni insisted, dismissing claims authorities were slow to react.
"We did everything possible to save lives as soon as we were alerted to a problem... we were not forewarned," said Meloni, whose far-right government takes a hardline stance on migration, during a visit to the United Arab Emirates.
The government is under pressure as it faces opposition calls for Interior Minister Matteo Piantedosi to resign.
The Italian judicial system is investigating the time it took for rescue services to reach the vessel, which left Turkey with some 200 migrants and went down off Steccato in the southern region of Calabria.
The death toll earlier reached 69 after authorities found the body of an infant aged around three.
Prosecutors in Crotone opened an investigation on Thursday into what went wrong in the rescue operation.
Two patrol boats dispatched by the Italian authorities were unable to intercept the wooden vessel owing to bad weather after Frontex reported spotting it the previous evening before it sank in stormy seas.
In an open letter to Meloni, the mayor of Crotone, Vincenzo Voce, slammed Meloni.
"The community of Crotone, struck by immense pain, awaited on your part a message, an appeal, a sign -- which was not forthcoming," wrote Voce.
"I am seeking solutions. Italy cannot resolve the problem alone -- but in order to prevent more people dying we must stop illegal departures," Meloni retorted.
Rome has been accusing its EU partners of not showing enough solidarity with Italy for years, after dealing with arrivals of tens of thousands of migrants.
The country's interior ministry says more than 14,000 migrants, including 1,700 minors, have reached Italian shores so far this year -- more than twice as many as for the same period last year.
