Former Labour Party TD Derek McDowell will stand in for deputy government press secretary Cathy Madden, who will take maternity leave next week.
Mr McDowell, a solicitor by profession, represented Dublin North Central between 1992 and 2002, and subsequently served as a senator until 2007. He also worked for Concern as head of advocacy.
He has contributed opinion pieces to The Irish Times in recent months.
Ms Madden, a former 98fm and Newstalk journalist, was appointed deputy government press secretary on the nomination of Labour in April 2011, having previously worked for the party in a media advisory role.