A former city child-services agency supervisor, assigned to investigate fraud, has been sentenced to nearly three years in prison for defrauding the agency out of more than half a million dollars.

Manhattan federal Judge Barbara S. Jones sentenced Nigel Osarenkhoe on Wednesday to 33 months in prison. She also ordered him to pay back nearly $564,000.

Prosecutors say Osarenkhoe — who oversaw internal reporting of adoption subsidies to families and also was a member of the agency’s quality-assurance unit — used his computer access to authorize fraudulent payments.