Irish Nationality and Citizenship Act 1956
Mutual citizenship rights.
26. —(1) Where the Government are satisfied that under the law of another country (whether by virtue of a convention between that country and the State or otherwise) Irish citizens enjoy in that country some or all of the rights and privileges of a citizen of that country, the Government may by order (in this section referred to as a citizenship rights order) declare that citizens of that country shall enjoy in the State similar citizenship rights and privileges to those enjoyed by Irish citizens in that country, but subject to such conditions (if any) as the Government may think fit to impose.
(2) Every citizenship rights order shall have effect in accordance with its terms.
(3) The Government may by order revoke or amend an order under this section.
(4) The Government shall not, by a citizenship rights order, confer upon a citizen of another country any right or privilege reserved by law to any class or group of persons, howsoever defined, of which he is, at the relevant time, not a member.
(5) Every order under this section shall be laid before each House of the Oireachtas as soon as may be after it is made, and if a resolution annulling the order is passed by either House within the next twenty-one days after that House has sat after the order was laid before it, the order shall be annulled accordingly but without prejudice to the validity of anything previously done thereunder.
(6) Every order made before the passing of this Act under section 23 of the Act of 1935 conferring citizenship rights on the citizens of another country shall continue in full force and effect until revoked or amended by an order made under this section.