The Communications Minister Pat Rabbitte has defended his decision to choose a new form of postcode for Ireland.
A private firm is being given a 10-year contract to roll out a postcode system in Ireland, with the process beginning this year.
At an Oireachtas committee Minister Rabbitte was criticised over the decision not to use a free system for assigning codes to every property.
Mr Rabbitte said the only difficulty with the process will be the need to update existing Government systems.
He said: "Ours will be a unique system.
"The reason that it will take 12 months to be brought into play is that other systems with which it is doing business and interacting will have to be brought into line.
"Databases will have to be brought into line and Government departments for example, and so on."