Consideration
61 It is necessary first to identify the nature of public interest immunity. As explained by the High Court in Jacobsen v Rogers, public interest immunity reflects public policy in the same way that legal professional privilege does. The principles of legal professional privilege were described at 589 as "a basic law doctrine" which is not to be abrogated except in the clearest of terms (referring to Baker v Campbell [1983] HCA 39; 153 CLR 52). The plurality considered that public interest immunity was also a basic common law doctrine and not a mere rule of evidence. The plurality said, at 589:
In Baker v Campbell, this Court held by a majority that the doctrine of legal professional privilege is not confined to judicial and quasi-judicial proceedings and extends to the compulsory disclosure of communications in extrajudicial proceedings. In particular, it was held to extend to search and seizure under a warrant issued pursuant to s. 10 of the Crimes Act. The majority referred to the principle that a basic common law doctrine is not to be abrogated except in the clearest of terms and held that s. 10, being silent upon the matter, did not exclude the doctrine of legal professional privilege. Public interest immunity reflects public policy as does legal professional privilege, although it has never been thought to be confined to judicial and quasi-judicial proceedings. In accordance with the approach adopted in Baker v Campbell, it is open to the Crown to resist the seizure under a s. 10 search warrant of documents to which public interest immunity attaches.
As is demonstrated by Baker v Campbell and by this case, if a dispute arises as to the existence of the immunity, means are available to obtain a judicial determination of the issue. In any event, practical difficulties in giving effect to the immunity in the context of the execution of a search warrant would seem to us to be an inadequate reason for holding the doctrine to be inapplicable. Such practical difficulties as exist are not insurmountable. That is demonstrated by the guidelines agreed in 1986 between the Australian Federal Police and the legal profession on the execution of search warrants on lawyers' premises where a claim of legal professional privilege is made.
(Footnotes omitted.)
62 We therefore approach the question of statutory construction in accordance with the principle of legality, that is, very clear words are required to exclude such a common law doctrine: see, by way of example: Potter v Minahan [1908] HCA 63; 7 CLR 277 at 304; Coco v The Queen [1994] HCA 15; 179 CLR 427 at 437-438; Re Minister for Immigration and Multicultural Affairs; Ex Parte Miah [2001] HCA 22; 206 CLR 57; X7 v Australian Crime Commission [2013] HCA 29; 248 CLR 92 at 153 [158] per Kiefel J; North Australian Aboriginal Justice Agency Ltd v Northern Territory [2015] HCA 41; 326 ALR 16 at [11] per French CJ, Kiefel and Bell JJ and [222] per Nettle and Gordon JJ.
63 Applying that principle of construction, it may be accepted that ss 36 and 36B "exclude the operation of any rules of law that relate to the public interest", being the words of s 36D(6) but those words are immediately followed in the subsection by the words "and would otherwise apply in relation to the disclosure of information, or a matter contained in documents" in proceedings before the Tribunal.
64 In our opinion, it is significant, in terms of the text and context provided by these provisions, that s 36 applies to the disclosure of information or the disclosure of any matter contained in a document, as does s 36B, but neither of those sections deals with answering questions at the hearing of a proceeding before the Tribunal. The sections which do deal with answering questions are s 36A in the case of the Commonwealth and s 36C in the case of a State. As may be seen, s 36D(6) has nothing to say to those provisions.
65 We have referred above to the reliance placed by the Tribunal on Re Pochi, which Brennan J decided in 1979. That case was determined not on the basis of public interest immunity but rather on the basis of formulating appropriate confidentiality orders under s 35 of the then Administrative Appeals Tribunal Act. It is significant to note that at the relevant time that Act did not contain the series of detailed provisions, inserted in 1988, dealing with certain public interest immunity claims by both the Commonwealth and the States. In 1979, it did, however, contain s 36 which dealt with the process to apply, including the role of the President (a Federal Court judge), if the Commonwealth Attorney-General certified that disclosure of information or documents would be contrary to the public interest on specified grounds. Section 36A was also in the Administrative Appeals Tribunal Act at that time and it dealt with a person answering questions in the course of giving evidence and the Attorney-General objected on the ground of public interest immunity. These provisions appear to have been based on an assumption that a public interest immunity claim could not otherwise be resolved within the Tribunal (see the reference in s 36(1)(c) to "a judicial proceeding"). In our opinion Brennan J proceeded on the basis that public interest immunity did not operate except in a court and did not apply in proceedings before the Tribunal, see especially at 512 of the report. Jacobsen v Rogers had not then been decided by the High Court. It is also notable that in a decision of the Full Court which also preceded Jacobsen v Rogers, Aboriginal Sacred Sites Protection Authority v Maurice (1986) 10 FCR 104, Bowen CJ said at 108 that it was "not entirely clear" whether public interest immunity applied to proceedings other than court proceedings. See also the dissenting judgment of Brennan J in Jacobsen v Rogers.
66 In our opinion, common law public interest immunity has not been displaced by the relevant provisions of the Administrative Appeals Tribunal Act relating to oral evidence.
67 We refer to the terms of ss 36(1) and (5) as originally enacted. The former provision provided that if the Commonwealth Attorney-General gave a certification, the following provisions in s 36 had effect. Subsection 36(5) provided that: "This section excludes the operation of any rules of law relating to the public interest that would otherwise apply in relation to the disclosure of information or of the contents of documents in proceedings before the Tribunal". The reference to "this section" necessarily imported s 36(1) which, in its terms, was confined to the situation where the Attorney-General gave a certificate. The provision was silent on the question of whether public interest immunity applied where no such certificate was given. Necessarily therefore, from the outset, any displacement of public interest immunity by the Administrative Appeals Tribunal Act was relatively limited. Although that was broadened by subsequent amendments, for the reasons given above those amendments did not have the effect of displacing common law public interest immunity in respect of oral evidence.
68 Re Suardana & Minister for Immigration & Ethnic Affairs (1980) 2 ALD 830; 49 FLR 8 was a case where, in respect of various exhibits, the Attorney-General certified that it would be contrary to the public interest to disclose the names of the informants in those documents as that disclosure would interfere with the effective detection and prevention of criminal offences in relation to drugs and which reason could form the basis for a claim by the Crown in right of the Commonwealth in a judicial proceeding. It may be noted that this decision was subsequent in time to the enactment of, but did not involve, s 36A of the Administrative Appeals Tribunal Act. The President, Davies J, considered the information in accordance with ss 36(3) and 36(4).
69 In Re Queensland Nickel, Gray J was dealing with an application for discovery of documents from the state of Queensland. Queensland had become a party to the proceedings. In resisting the application, the Solicitor-General for the state of Queensland appeared and relied on a certificate of the Attorney-General for the state of Queensland pursuant to s 36B. The certificate made claims in respect of certain documents and information in documents. Gray J said as follows:
(10) It is plain from s 36D(6) that s 36B is intended to operate as a code, whenever an Attorney-General of a state certifies in terms of subs (1). Any common law rule is specifically excluded by s 36D(3)-(6).
(11) Nevertheless, regard must be had to the common law in at least one respect. The operation of s 36B so far as subs (1)(b) is concerned, depends upon the existence of a certified reason that could form the basis for a claim by the Crown in right of the state in a judicial proceeding that information or matter contained in a document should not be disclosed. It is necessary to look to the common law, to ascertain when such a claim could be made in a judicial proceeding. There can be no doubt that s 36B(1)(b) is intended to specify that immunity from disclosure of the contents of documents which used to be known as Crown privilege, but has become known as public interest immunity. The nature of this immunity, and the principles to be applied in determining whether it exists are conveniently set out in a passage in the judgment of Gibbs ACJ in Sankey v Whitlam (1978) 142 CLR 1 at 38- 46. For the purposes of this proceeding, the important point is that s 36B(1)(b) can only be invoked in circumstances in which public interest privilege could have been claimed, were the proceeding a judicial one. That immunity can be claimed whether or not the Crown is a party to a particular proceeding, if the Crown is called upon to produce documents. In circumstances in which the Crown is a party to an application before the tribunal, and in which it has available to it the privileges of a private litigant, such as the privilege of refusing to divulge communications with its legal advisers, or communications made without prejudice, the section does not have any operation with respect to those privileges.
(12) Once a claim for immunity has been determined to fall within s 36B(1)(b), the principles upon which it is to be determined are laid down by s 36B(5). These principles may well differ from those which would apply under the common law in a judicial proceeding …
In our opinion, Re Queensland Nickel does not deal with the present question which arises in relation to oral evidence and where the Attorney-General is not otherwise a party and has not certified.
70 For completeness, we note the observations of French J, as his Honour then was, in Re Grant & Australian & Overseas Telecommunications Corp (1992) 16 AAR 66, to which we were taken. That case concerned a summons to the Vietnam Veterans' Counselling Service to produce certain documents. The Attorney-General for the Commonwealth signed a certificate pursuant to s 36(1) stating that the disclosure of matters specified in the summons was contrary to the public interest because it would severely inhibit the effectiveness of the Service from operating as a confidential counselling service and any breach of confidentiality of the Service would inhibit its effectiveness. Thus, the decision does not deal with the present question of oral evidence. We refer to it insofar as French J said that s 36D(6) in a sense may be seen as a rule for the interpretation of s 36 and did not of its own force exclude the operation of such rules of law, but that s 36 had that effect. French J cited Re Queensland Nickel to the effect that the equivalent of s 36 in relation to State Attorneys-General, s 36B, was intended to operate as a code. His Honour said that the practical operation of s 36D(6) was hard to envisage. It did not prevent a consideration under s 36(4) of a wide range of factors related to the immunity question.
71 We have also referred above to the reliance placed by the Tribunal upon s 130 of the Evidence Act \in concluding that public interest immunity was no longer a substantive rule of law, but rather is a rule of evidence. This reasoning was used to distinguish Jacobsen v Rogers. In [42] of the Tribunal's reasons for decision, it was said that, by enacting s 130 of the Evidence Act, the Parliament was "resolving" the dispute whether public interest immunity was a common law doctrine by characterising it as a rule of evidence. In our respectful opinion, the Tribunal failed to appreciate the limited nature of s 130 of the Evidence Act and its non-application to pre-trial steps prior to evidence being adduced in curial proceedings, such as discovery and notices to produce: (see, Esso Australian Resources Ltd v Commissioner of Taxation [1999] HCA 67; 201 CLR 49). This limitation has been overtaken in some State and Territory evidence legislation (see s 131A) but not at the Commonwealth level. There has never been any doubt that public interest immunity has effect in a court and is therefore a rule of evidence. Thus, the Evidence Act only applies to proceedings in a Federal Court or in a body which is required to apply the rules of evidence (see s 4). To say that, however, is to say nothing about public interest immunity outside a court as a substantive rule of law.
72 In our opinion, when the matter of oral evidence where there is a claim to public interest immunity is analysed by reference to the principles that public interest immunity is a basic common law doctrine and not merely a rule of evidence; and that public interest immunity applies to bodies other than courts, including the Tribunal; and, that in accordance with the principle of legality, words of irresistible clarity are required to exclude such a common law doctrine, the provisions in the Administrative Appeals Tribunal Act relied upon by the Tribunal do not rise to that level. As we have said, notably s 36D(6) does not apply to s 36C and we do not construe s 36C as excluding a claim to public interest immunity. Furthermore, there is no other indication that s 36C was intended to preclude anyone other than the State Attorney-General from claiming public interest immunity, whether it be the Tribunal itself or another State agency, such as the Commissioner of Police.
73 In light of this conclusion, since the application before the Court concerned only oral evidence, it is not necessary for us to consider whether s 36C operates as a code, in the sense that it operates only where an Attorney-General of a State informs the Tribunal of his or her opinion.
74 It is also appropriate to question the practicality of the Tribunal's approach in relation to oral evidence. If it be the case that only the Attorney-General of the State can give a certificate in the circumstances envisaged in s 36C, it would mean that whenever an issue of public interest immunity arose in relation to oral evidence in a case to which the Attorney-General is not a party, an adjournment may well be needed to enable the Attorney-General to be notified and given time to consider whether a certificate should issue. There would be considerable practical inconvenience in having the Attorney-General attend every hearing in which it was feared that a public interest immunity issue might arise, even allowing for the fact that s 36(7) contemplates that the Attorney-General can appear through a legal representative or some other person.
75 As we have noted, Mr Guo relied on Applicant VEAL of 2002 at [23]-[26]. In our opinion that authority does not stand for the proposition that public interest immunity does not apply in the Tribunal. The High Court was dealing with procedural fairness in the Tribunal and indicating how the Tribunal might mould its procedures, by analogy with the courts' accommodation of public interest immunity, so as to afford procedural fairness consistently with ensuring that information that had been supplied by an informer was not denied to the Executive government when making its decision. It is not at all clear that the letter making allegations against the appellant could have been the subject of a claim to public interest immunity. What is clear is that no such claim is identified in the unanimous judgment of the High Court.
76 We note that the parties to the application accepted the correctness of the decision of the Full Court in Australian Securities and Investments Commission v P Dawson Nominees Pty Ltd [2008] FCAFC 123; 169 FCR 227 at [23]-[24] where it was held that a balancing exercise was required even in a claim based on protecting an informer's identity and that there was "no point in attempting categorisation [of the public interest] into different levels of importance".
77 We also note for completeness that although notices under s 78B of the Judiciary Act were sent to the Attorneys-General, at the suggestion of the Court, directed to:
(a) the legislative power of the Commonwealth Parliament to enact ss 33, 35, 36, 36A, 36B, 36C, 36D, 37 and 39 of the Administrative Appeals Tribunal Act 1975 (Cth); and
(b) whether as a matter of construction of those provisions
the Tribunal is authorised to regulate the manner in which a claim to public interest immunity by the Commissioner of Police (NSW) may be maintained in the Tribunal and to require answers the subject of such a claim by the Commissioner of Police (NSW) to be given to the Tribunal
neither the applicant Commissioner nor any Attorney-General sought to raise such an issue, whether by reference to Melbourne Corporation v Commonwealth [1947] HCA 26; 74 CLR 31 or otherwise, before this Court. Indeed, counsel for the applicant Commissioner accepted that the State of New South Wales was in no different position to the Commonwealth so far as concerned the issue of displacement or modification of public interest immunity. Counsel for the applicant Commissioner was content for the Court to proceed directly from the construction of the provisions of the Administrative Appeals Tribunal Act so far as they concern the Commonwealth executive, to apply that same construction to the provisions so far as they concern the State.