Kwesi Ofori, a police spokesman, said: "There were 150 passengers on board but only 30 have been rescued. The rest are feared dead."
Ofori said the accident happened on Saturday and that a search party was still looking for survivors.
He said the boat was probably overloaded and had hit a stump as it travelled across the lake, one of the world's largest reservoirs.
The passengers had been travelling from Dudzome, in the Afram Plains region, to Abotoase further east.
The bodies of three young children had been recovered from the accident site.
Local media reported that the passengers were being moved after settling illegally in a forestry reserve in Dudzome and had been forced with their property and livestock onto a boat that should only carry 70 people.
"There were 150 passengers on board but only 30 have been rescued. The rest are feared dead"
Kwesi Ofori, police spokesman
An overloaded wooden boat carrying three times the number of passengers it was built for sank off Djibouti last week, killing at least 109 people in one of the Red Sea nation's worst disasters.
At least 127 people drowned last month after a wooden boat travelling from Nigeria to Gabon broke up in high seas and sank off Cameroon's Atlantic port of Kribi.
Survivors said more than twice the registered 150 passengers had been onboard.