4.— (1) Notwithstanding any other enactment but subject to subsection (2), every member of the Permanent Defence Force shall be liable to serve outside the State—

(a) with a contingent of the Permanent Defence Force despatched for service with an International United Nations Force under section 2 of the Act of 1960, or

(b) with a contingent or as a member despatched for service for any purpose specified in section 3 of this Act.

(2) Subject to subsection (3), a member of the Permanent Defence Force appointed or enlisted before 1 July 1993 shall not be liable to serve outside the State with a contingent of the Permanent Defence Force despatched for service outside the State as part of an International United Nations Force unless that force is a force or body established by the Security Council or the General Assembly of the United Nations for the performance of duties of a police character.

(3) Where a member of the Permanent Defence Force (being a member specified in subsection (2)) has offered in writing, whether before, on or after the date of passing of this Act, to render himself liable for service outside the State during a specified period as part of an International United Nations Force (other than a force or body established by the Security Council or the General Assembly of the United Nations for the performance of duties of a police character) and the Minister or an officer authorised in that behalf by the Minister has accepted the offer, subsection (1) shall also apply to that member during that period.