However, state media said the bus fell off the ferry while boarding.
Among the dead were six children aged between two and 13, authorities said.
There were conflicting reports about the minibus driver, with one report saying he had drowned and others saying he had turned himself in to authorities, fearing retribution from the families of those killed.
Series of accidents
Many of the dead were from an extended family who had been travelling back to Cairo after spending the holiday with family, the state MENA news agency reported.
A series of deadly accidents involving Egypt's ferry system has led to public anger over the government's handling of transport safety.
Many of the accidents have occurred on public holidays, when Egypt's transport system becomes overloaded.
In October at least four people died, also in Minya, when passengers fell into the Nile as they tried to board a ferry.
And in February 2006 about 1,000 people died when a ferry sank in the Red Sea as it travelled to Egypt from Saudi Arabia.