Djotodia overthrew Bozize in March and was sworn in Aug 18 as head of the transitional government. The takeover was condemned as a coup.
Citing a statement from the presidential office, the radio Wednesday said the clashes since Saturday have caused 150 or so casualties, including almost 100 people killed in the fighting and 50 injured, Xinhua reported.
Bossangoa and Bouca are among the worst hit areas northwest of the capital Bangui, it said.
Bossangoa, the home region of Bozize, has become another hotspot since the rival forces fought in the districts seen as his strongholds in Bangui last month.
While Djotodia's Seleka fighters are trying to disarm the pro- Bozize elements, the latter seem to manoeuvre for a comeback of their leader.
Levy Yakete, spokesperson for Bozize, recently said the attacks were launched by former armymen who want to bring Bozize back for the mandate as the president elected by his people.
The Economic Community of Central African States has provided for a transitional period of 18 months, pending an election to end the crisis.
A 1,400-strong peacekeeping mission is deployed in the troubled country, which has witnessed repeated coups since independence from France in 1960.