Rescuers are searching for survivors after the converted fishing boat – carrying about 130 people – ran into trouble as it tried to reach an island off Nampula.
So far, 94 people have been confirmed dead after the disaster – with many of the victims said to be children.
Nampula’s secretary of state, Jaime Neto, said: “Because the boat was overcrowded and unsuited to carry passengers, it ended up sinking.”
He said the passengers were trying to escape a cholera outbreak on the mainland.
Unverified video footage on social media appeared to show dozens of bodies lined up on a beach.
Another appeared to show people on small boats pulling bodies out of the water.
The fishing boat was said to be travelling from Lunga to Mozambique Island.
Nampula province has been one of the worst-affected by the cholera outbreak – with 15,000 cases and 32 deaths recorded since October, according to government data.
More to follow.