The Chief of the Defence Force or a service chief may, by instrument in writing, appoint an officer, or each officer included in a class of officers, to be a superior authority for the purpose of:
(a) representing the interests of the Defence Force in relation to charges that are being considered by the Director of Military Prosecutions for possible trial by a Defence Force magistrate or a court martial; and
(b) exercising the powers and performing the functions conferred on superior authorities by or under this Act or the regulations.