The Environment Minister Phil Hogan is reminding people that today is the last day to apply for inclusion on the supplementary register.
People who are eligible to vote, but are not registered, have until the end of the day to make sure of their ballot in the Stability Treaty on May 31.
Anyone not sure whether they are on the register should go to www.checktheregister.ie, where they can also download an application form.
Forms can also be found at all City or County Councils.
To be eligible for inclusion in the supplement to the register a person must be an Irish citizen, of 18 years of age by polling day and must be ordinarily resident in the State.