The State Commissioner for Health, Dr. Nicholas Azinge confirmed the development to Channels Television.
Three of the suspected cases have been treated and discharged.
Two of the cases are still being treated at the Federal Medical Centre in Asaba, the state capital.
Dr. Azinge says samples of the patients have been sent to the World Health Organisation for confirmation.
The Federal Government had earlier announced 74 suspected cases of monkeypox virus in 11 states in the country.
Minister of Health, Professor Isaac Adewole, disclosed this to State House correspondents on Wednesday at the end of the Federal Executive Council meeting in Abuja.