69 In addition, under s 15AA of the Acts Interpretation Act 1901 (Cth), the interpretation that would best achieve the purpose or object of the Act (whether or not that purpose is expressly stated) is to be preferred to each other interpretation. As there recognised, the purpose of an enactment may be expressly stated, but it may also be discerned by implication from the text, read in its proper context. The express objects of the FOI Act (summarised at [11] above) are relevant, but as the plurality cautioned in Kline v Official Secretary to the Governor General (2013) 249 CLR 645 (at [37]):
The FOI Act does not pursue its objects, as legislative purposes, at any cost. The statutory scheme is complex in achieving a balance between the exposure of some government processes and activities to increased public participation and scrutiny, by making information freely available to persons on request, and exempting other government processes and activities from public participation and scrutiny, in order to secure a competing or conflicting public interest in non-disclosure. A clear example is the exemption of ASIO from the operation of the FOI Act.
(footnote omitted)
70 See also Carr v Western Australia (2007) 232 CLR 138, Gleeson CJ (at [5]); Construction Forestry Mining and Energy Union v Mammoet Australia Pty Ltd (2013) 248 CLR 619, Crennan, Kiefel, Bell, Gageler and Keane JJ (at [40]–[41]).
71 As a preliminary contextual matter, it is to be borne in mind that if there is a temporal element of the kind asserted by Mr Patrick in relation to a document that is an "official document of a Minister" then it would ordinarily follow that the same temporal element applies in operative provisions employing the phrase "document of an agency". Neither party suggested otherwise.
72 Before turning to the more contentious issues, it is necessary to say something about the meaning of the words "Minister" and "possession" as they appear throughout the FOI Act.
Possession
73 The word "possession" is not defined. As French CJ said in Momcilovic v The Queen (2011) 245 CLR 1 (at [16]):
… The word 'possession' embodies 'a deceptively simple concept' which has never been completely and logically and exhaustively defined and may vary according to its statutory context. It has been described as 'always giving rise to trouble'. Nevertheless, there are certain essential elements of the concept. Possession of a thing ordinarily involves physical custody or control of it. …
(footnotes omitted)
