The granting of Irish citizenship through naturalisation is governed by the provisions of the Irish Nationality and Citizenship Act 1956, as amended. All applications for a certificate of naturalisation are processed and assessed individually in accordance with the provisions of the Act.
It is open to the person concerned to make a further application for the grant of a certificate of naturalisation at any time. If the person concerned believes the error was on the part of the Department they can contact Citizenship Division and they will reexamine the calculation of residence.
There is no time limit within which an unsuccessful applicant can make a new application, nor is there any limit on the number of applications made. Applicants are advised that in making any new application they should bear in mind the reasons for the previous refusal. Each application is examined individually and assessed on their own merits.
Detailed information on how to apply for naturalisation, including a residency calculator resource, is available here: www.irishimmigration.ie/how-to-become-a-citizen/