Monica Riordan was last seen on CCTV on Sir John Rogersons Quay Dublin around 7pm on the 20th December 2011.

Monica is of average height and of thin build with shoulderlength blonde hair. When last seen she was wearing a long grey coat, dark jeans and grey/white runners.

Anyone with information is asked to contact the Gardaí at Pearse Street Garda Station on 01 666 9000, any Garda Station, or the Garda Confidential line on 1800 666 111