Divers managed to recover the bodies of 15 more victims from the wreck of the Esther Miracle, public prosecutor Andre Patrick Roponat said.
The vessel went down overnight Wednesday to Thursday carrying 161 passengers and crew from the capital Libreville to the oil town of Port-Gentil.
One hundred and twenty-four people have been rescued since the incident.
An earlier toll had put the number of dead at six.
Roponat said the latest 15 victims had been found in the ill-fated boat and brought out of the water by divers.
"All were wearing life jackets. They were stuck in the boat," he said, adding the bodies had been taken for identification.
"The search continues," he said.
Two inquiries have been opened and the government has announced the suspension of four officials as a precautionary measure.
The prosecutor also said there had been some cases of people being taken into custody and also of being questioned but gave no details.
Most of the 124 survivors were picked up off Libreville after dawn on Thursday by locals in dugout canoes, fishermen, an oil barge and a navy patrol boat.
Gabon Ferry Sinking Toll Rises
LIBREVILLE - The death toll from a ferry disaster off the coast of Gabon last week has risen to 21 and the search continues for 16 people still missing, the public prosecutor said Tuesday.
