The overloaded boat was on its way to a wedding with around 100 passengers when it capsized on the Indus River near Sadiqabad.
So far, 26 bodies – mostly women and children – have been salvaged. At least as many are missing and presumed dead.
“It has been more than 48 hours since the incident, so there is no longer any chance of finding survivors,” Kashif Nisar Gill, a spokesman for the local authorities, told AFP.
Most of the survivors are men who managed to swim ashore, according to Gill.
Women are rarely encouraged to learn to swim in Pakistan because traditional values stand in the way.