The Registrar General Kieran Feely has raised concerns at the abuse of the Irish marriage registration system.
Mr Feely said it was the estimate of the General Register Office that 600 to 700 "marriages of convenience" take place in Ireland every year.
It is normally for the purpose of securing residency rights.
Mr Feely said there is currently no legislative basis to stop suspected sham marriages.
However, the Government has promised to introduce new laws to give registrars greater power to act.