Dr Kevin McCoy, chief inspector of the Inspectorate of Social Services in Northern Ireland, has been appointed to the Republic's Commission to Inquire into Child Abuse.
Dr McCoy replaces Mr Bob Lewis, who resigned earlier this year from the commission, which is headed by Ms Justice Laffoy.
Dr McCoy was a social work adviser in the Department of Health and Social Security in Northern Ireland from 1972 to 1986, when he was appointed assistant chief inspector of the Social Services Inspectorate. He became chief inspector in 1989.
He has worked with the Department of Health and Children on establishing a social services inspectorate in the Republic, and as a consultant in drawing up the Children First guidelines on child abuse.