23. (1) The Minister, on application made in writing by a member of the Garda Síochána not below the rank of Assistant Commissioner, may vary an authorisation or extend the period during which the authorisation shall remain in force.

(2) Sections 21 and 22 shall apply to an application for the variation or extension of an authorisation, as if the references in those sections to an authorisation were references to the variation or, as the case may be, extension of an authorisation.