Local transport minister Laurent Sumba Kahozi said the search for survivors was continuing.
Rescue workers found passengers in the water on Sunday, clinging on to petrol cans and other objects.
Correspondents say such accidents are fairly common in the region as ferries are often overloaded.
Life jackets are also often missing and many people cannot swim.
Officials in Katanga province said strong winds and overloading caused the boat, the MV Mutambala, to capsize.
A number of women and children were among the victims in the disaster, which happened in the early hours of Friday morning.
Initial reports said 26 people had died.
The number of survivors stands at 232, mostly men, the provincial minister for transport said.
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