Mr Onogwu Mohammed, Chief Press Secretary to Bello, confirmed the appointment in a statement issued on Friday in Lokoja.
Mohammed said Olusuyi would function in that capacity pending the appointment of a substantive CJ.
The position became vacant, following the death of Justice Nasir Ajanah on June 29.
Similarly, the appointment of Justice Bayo Olowosegun as the acting President of the state’s Customary Court of Appeal by the governor, was also announced in the statement.
Olowosegun’s appointment also followed the demise of former occupant of the office, Justice Shaibu Atadoga, who died on June 22.
Both appointments are for an initial period of three months, the government disclosed in the statement.