A presidential decree broadcast on state radio on Monday said three days of national mourning would be observed in memory of the victims of the "tragic" incident.
Authorities have said 58 bodies were retrieved from the Mpoko River in the capital Bangui after the vessel capsized last Friday as it was taking people to the funeral of a village chief. The wooden boat was carrying more than 300 people, some standing, according to witnesses and videos on social media. Shortly after setting off, the flat-bottomed "whaler" boat gave way under the weight of the passengers onboard.
Search operations are continuing, and the provisional death toll could rise.
A government spokesman last Saturday announced an inquiry would be opened to establish the causes and responsibility. He also said a support system would be set up for victims' families.
Video images on social media showed people trying to swim to the bank and others rescued by fishermen in dugout canoes known as pirogues and nearby sand dredgers before rescuers arrived.
River transport is a key way of getting around the Central African Republic due to the poor state of the roads. Whaler boats are common in Central Africa but are often dilapidated, overcrowded and also used to carry goods and cattle.
In 2015, a river barge was destroyed in a fire after the engine exploded, leaving 100 people missing in the Ubangi River.