MASON C.J., BRENNAN, DAWSON, TOOHEY AND GAUDRON JJ. These appeals concern the issuing of warrants under State legislation purporting to authorize Australian Federal Police officers to install and use listening devices in the course of investigating alleged narcotics offences, in circumstances where such use by a member of the Australian Federal Police would be prohibited by federal legislation. The central question raised is whether and to what extent the warrants so issued are invalid as a result of that prohibition.

2. Nine warrants were issued between 20 March 1987 and 18 August 1987 by judges of the Supreme Court of New South Wales under Pt 4 of the Listening Devices Act 1984 (N.S.W.) ("the State Act") upon application of the New South Wales Commissioner of Police. The applications arose from investigations being conducted by State and federal police officers into alleged narcotics offences. The warrants recited in each case that the Court was satisfied that there were reasonable grounds for the belief of the Commissioner that four federal offences and two State offences "have been and are likely to be committed". The warrants authorized the use of listening devices by a named State police officer and "on his behalf" named State and federal police officers "to record or listen to the private conversations" of certain persons, including the appellants, and authorized the installation of devices on and their retrieval from specified premises and entry onto those premises for those purposes. Each warrant fixed a period during which it was to remain in force.

3. On 25 August 1987 the appellants were arrested and charged with offences under New South Wales law relating to the supply of a prohibited drug, namely heroin. In the course of the ensuing committal proceedings, the Crown indicated that it would seek to use in evidence certain tape recordings made with the use of listening devices purportedly authorized by the warrants. The appellants objected to the placing of the tapes into evidence and contended that the warrants were invalid. The magistrate ruled on 13 January 1988 that the warrants were valid and that the tapes were admissible. The appellants then sought declarations in the Supreme Court of New South Wales that the warrants were invalid and of no legal effect and orders setting them aside. The claim was referred by Lee J. to the Court of Appeal. Notwithstanding that committal proceedings in relation to the offences already mentioned were pending at that time, the Court of Appeal agreed to deal with the matter at the request of the parties.

4. Section 5(1)(a) of the State Act prohibits a person from using a listening device to record or listen to a private conversation to which he or she is not a party. However, s.5(1) does not apply to "the use of a listening device pursuant to a warrant granted under Part 4" of the Act or to the use of a listening device pursuant to an authority granted by or under the Telecommunications (Interception) Act 1979 (Cth) or any other law of the Commonwealth: s.5(2)(a) and (b).

5. Part 4 deals with the issue of warrants. Section 16(1) provides that, upon complaint by a person that he or she suspects or believes that a prescribed offence has been, or is about to be or is likely to be, committed and that, for the purpose of investigating the offence or enabling evidence to be obtained, the use of a listening device is necessary, the Supreme Court may, if satisfied "that there are reasonable grounds for that suspicion or belief, authorise, by warrant, the use of the listening device". Prescribed offences include offences against State and federal law. The court is required to have regard to various matters set out in s.16(2), and sub-ss.(3) and (4) require particular matters to be dealt with in the warrant. A warrant is required to specify various matters, including the prescribed offence in respect of which the warrant is granted, where practicable the name of any person whose private conversation may be listened to or recorded, the period (being not more than twenty-one days) during which the warrant is to be in force, the name of any person who may use a listening device pursuant to the warrant, the persons who may use the device on behalf of that person and the time in which the person authorized is required to furnish a written report under s.19 to the court and to the Attorney-General: s.16(4).

6. Notice of an application for a warrant is required to be served on the Attorney-General, who must have had an opportunity to be heard in relation to the granting of the warrant before it is granted: s.17. Proceedings in the court under Pt 4 are regulated by rules of court but must be conducted in the absence of the public: s.21.

7. The objection to the validity of the warrants in the present appeals is founded upon provisions of Div.1A of Pt XII of the Customs Act 1901 (Cth) as they affect the activities of members of the Australian Federal Police in the course of making "narcotics inquiries". It is not disputed that the investigations in this case came within the ambit of that expression. Section 219B of the Customs Act provided at the relevant time, so far as is material:

accordance with a warrant issued under Div.1A, by a member of the Australian Federal Police or a person acting by arrangement with such a member is not unlawful, notwithstanding any law of a State or Territory.

8. The issue of warrants under Div.1A is dealt with in s.219B(5)-(10). An application for the issue of a warrant may be made to a judge of the Federal Court, a judge of the Supreme Court of the Australian Capital Territory or of the Northern Territory, or any State Supreme Court judge exercising jurisdiction pursuant to s.11 of the Customs Act. The judge is required to be satisfied of certain matters, including (a) that the person in relation to whom the listening device is sought to be used has committed or is suspected on reasonable grounds of having committed or of being likely to commit a narcotics offence; and (b) that the use by members of the Australian Federal Police of a listening device to listen to or record words spoken by or to that person will, or is likely to, assist the Australian Federal Police in or in connection with (i) inquiries made in relation to a narcotics offence that the person has committed or is reasonably suspected of having committed; or (ii) inquiries made in relation to the likely commission by the person of a narcotics offence where there are circumstances reasonably giving rise to the suspicion that he or she is likely to commit that offence: s.219B(5). The expression "narcotics offence" is defined to mean "an offence punishable as provided by section 235" of the Customs Act: s.219A(1). If so satisfied, the judge may by warrant authorize members of the Australian Federal Police to use a listening device for the purpose of listening to or recording words spoken by, to or in the presence of the particular person in relation to whom the warrant was sought: s.219B(5). Similarly, the warrant may authorize entry onto premises for the purpose of installing, maintaining, using or recovering a listening device: s.219B(5). Section 219B(7) provides in similar terms for the application for and issue of a warrant in relation to particular premises.

9. In the Court of Appeal, McHugh J.A. (with whom Kirby P. agreed) found that s.219B covered the field in connection with the use of listening devices for the purposes of the investigation of federal narcotics offences by members of the Australian Federal Police. His Honour held that the State Act was invalid in so far as it purported to authorize a member of the Australian Federal Police or a person acting by arrangement with such a member to obtain a warrant to use a listening device for the purposes of narcotics inquiries as defined by the Customs Act. The case in the Court of Appeal had proceeded on the basis that the acts of the judges who issued the warrants were judicial rather than administrative acts, and McHugh J.A., after expressing misgivings as to that assumption, proceeded to consider whether the warrants could be severed on that basis. His Honour concluded that there was no difficulty in disregarding the parts of the warrants which in his view were unauthorized by reason of the operation of s.109 of the Constitution. Since the appellants could not show that the warrants would not have been issued without the inclusion of those parts, they had failed to prove that the warrants were wholly invalid. Accordingly, a claim for delivery up of the recordings, transcripts and other material evidencing the interception of the conversations was refused. However, the Court of Appeal declared that the warrants were of no effect in so far as they purported to authorize members of the Australian Federal Police or persons acting by arrangement with them to use listening devices for the purposes of narcotics inquiries being made by the Australian Federal Police.

10. Mahoney J.A. found that the warrants purported to authorize the Australian Federal Police to do what they could not lawfully do without a warrant under s.219B of the Customs Act. In his Honour's view, the warrants could be construed so as to operate subject to the limitations arising from the federal Act, either in accordance with general principles of construction or by virtue of s.32 of the Interpretation Act 1987 (N.S.W.), concerning the construction of "instruments". On this basis, Mahoney J.A. held that the warrants were not wholly invalid and expressed his agreement with the orders proposed by McHugh J.A.

11. In this Court the appellants contended that the warrants were judicial orders affected by fundamental defects so that persons prejudiced were entitled ex debito justitiae to have them set aside. They said that no question of severance arises, as the granting of each warrant was a single judicial decision. But in any event, they argued, the warrants were bad on their face and could not be preserved by assuming that they would have been issued in valid terms if the judges issuing them had been made aware of the relevant provisions of the Customs Act. The appellants sought delivery up or destruction of the tapes and any copies or transcripts which had been made.

12. The respondents in turn argued that the only relevance of the warrants in this case was their tender in committal proceedings for State offences in connection with the admissibility of evidence obtained pursuant to them. According to the respondents' argument, s.219B of the Customs Act did not concern the use of a listening device for the purpose of inquiring into a State offence and so s.109 of the Constitution did not invalidate the State Act in its application to the warrants in their use in the present case. In the alternative, the respondents contended that the warrants were capable of being severed by deleting any reference to the federal offences, or, if the result of a judicial act, were capable of variation as ex parte judicial orders. In either event, there was no ground for ordering delivery up or destruction unless the warrants were wholly invalid. Although they argued in the alternative, the respondents in this Court preferred the view that the issue of the warrants was an administrative and not a judicial act. Further, the respondents sought special leave to cross-appeal against the decision of the Court of Appeal in so far as it held that s.219B(2) of the Customs Act applied to members of the New South Wales Police engaged in joint drug investigations with members of the Australian Federal Police.

13. As any relevant limitation upon the power of the Supreme Court of New South Wales to issue a warrant must arise from an inconsistency with the provisions of the Customs Act, it is necessary first to determine what, if any, inconsistency exists between the two sets of statutory provisions. Two kinds of inconsistency could arise. First, there may be direct conflict between the prohibition in the Customs Act and the permissive operation of the State Act. Secondly, the Customs Act may evince an intention to cover the field in relation to the authorization of the use of listening devices by members of the Australian Federal Police engaged in narcotics inquiries and persons acting by arrangement with them.

14. It may be observed at once that there is, for present purposes, at least one area in which there is plainly no inconsistency. The federal Act does not purport to regulate the activities of State or federal police using a listening device other than for the purposes of federal narcotics inquiries. Moreover, it is clear from s.219B(4) of the Customs Act and s.5(2)(b) of the State Act that a person who uses a listening device pursuant to a warrant issued under the Customs Act does not thereby breach the State Act.

15. The possible area of direct inconsistency concerns the case where a person uses a listening device pursuant to a State warrant in circumstances which, in the absence of a federal warrant, would attract the prohibition contained in s.219B(1) or (2) of the federal Act. However, in order that such an inconsistency should exist, the State Act would need to purport to authorize the doing of an act rendered unlawful by the Customs Act. If the State Act purports to have that effect, it does so only indirectly by the medium of the warrant. The State Act itself does not positively authorize the use of listening devices, but provides that the use of a device under a warrant is not a contravention of s.5(1). No intention is manifested by the Act that the granting of a warrant should authorize that which would be illegal by virtue of the Customs Act. As far as the State Act itself is concerned, the provisions governing use of listening devices are not relevantly inconsistent with the Customs Act. It will be necessary to consider shortly whether or not a warrant issued under the State Act is itself capable of giving rise to an inconsistency for the purposes of s.109 of the Constitution.

16. The conclusion that the State Act does not purport to permit breaches of federal law compels the further conclusion that the Customs Act is not inconsistent with that Act by virtue of an intention to cover the field in relation to the use of listening devices by members of the Australian Federal Police and persons acting by arrangement with them in the course of federal narcotics inquiries. The fact that the State Act recognizes the grant of a federal warrant and exempts the use of a listening device pursuant to a federal warrant from the prohibition in s.5(1) indicates that the field covered by Div.1A of Pt XII of the Customs Act is one into which the State Act does not purport to intrude. If a federal warrant is required and issued, then a State warrant is not required. If no federal warrant is required, or if a federal warrant is required but not issued, then a State warrant is required, but that is not inconsistent with a federal warrant being required if the Customs Act so insists. Accordingly, the fact that a State warrant may be issued pursuant to the terms of s.16 of the State Act does not in any way give rise to an inconsistency with the federal Act.

17. The next question is whether a warrant issued pursuant to the State Act is itself capable of giving rise to any inconsistency with the Customs Act. Such an inconsistency could not arise unless the warrant is a law of the State. But that question may be put to one side. It is first necessary, in order to consider the operation of the warrant, to determine whether the act of issuing it is judicial or administrative in nature. If the issuing of the warrant is an administrative act, then the ambit of the warrant must be determined in the light of the scope of the power conferred upon the court by the statute. On that footing the ultimate effect of the warrant depends upon the construction of the power and of the warrant itself. The construction of the warrant may give rise to a question of severance. On the other hand, if the act of issuing a warrant is judicial in nature, then the warrant takes on the attributes of a judicial order. In that event, the appellants argue that the warrants in the present case are judicial orders issued in excess of jurisdiction and as such they cannot be severed or read down. Accordingly, they must be declared void and set aside. That is how the argument runs. However, the respondents contend that, even if the warrants are judicial orders, they are capable of being varied to the extent, if any, of their invalidity, so as to preserve their operation in respect of the use of listening devices in relation to the offences against State law with which the appellants have been charged.

18. On the arguments which have been presented to this Court, the question in the present case is whether a warrant issued under s.16 is a judicial order. In one sense - a loose sense - the warrant is a judicial act; it is an instrument issued by a judge of the Supreme Court. But the fact that it is an instrument issued by a judge of the Supreme Court does not stamp it with the character of a judicial order unless the warrant issues as a result of a determination made by the judge in his or her judicial capacity. To borrow the language of Lopes L.J. in Royal Aquarium and Summer and Winter Garden Society v. Parkinson (1892) 1 QB 431 at p 452:

"The word 'judicial' has two meanings. It

may refer to the discharge of duties

exercisable by a judge or by justices in

court, or to administrative duties which need

not be performed in court, but in respect of

which it is necessary to bring to bear a

judicial mind - that is, a mind to determine

what is fair and just in respect of the

matters under consideration."

19. Where a statute confers power on a court or a judge there is the question whether the power is conferred upon the court or the judge as such: Hilton v. Wells [1985] HCA 16; (1985) 157 CLR 57 at p 72. It has been said that where the power is conferred on a court, there is ordinarily a strong presumption that the court as such is intended: Hilton v. Wells at p 72. But the presumption is rebuttable and one of the important factors to be taken into account in determining that question of construction is whether the nature of the power is judicial: Hilton v. Wells, at p 73.

20. The characterization of a power as judicial or non-judicial in nature arises most frequently in connection with the rule that Ch.III of the Constitution does not allow the judicial power of the Commonwealth to be exercised "by a body established for purposes foreign to the judicial power" and does not allow "a combination with judicial power of functions which are not ancillary or incidental to its exercise but are foreign to it": Reg. v. Kirby; Ex parte Boilermakers' Society of Australia [1956] HCA 10; (1956) 94 CLR 254 at p 296. That of course is not a restriction which applies to courts exercising power other than the judicial power of the Commonwealth. But the decisions of this Court relating to the exercise of judicial power in the particular context of Ch.III give expression to the settled principles governing the exercise of judicial power generally.

21. Judicial power has proved to be insusceptible of comprehensive definition, though its broad elements were identified by Griffith C.J. in Huddart, Parker & Co. Proprietary Ltd. v. Moorehead [1909] HCA 36; (1909) 8 CLR 330 at p 357: see Labour Relations Board of Saskatchewan v. John East Iron Works Ltd. (1949) AC 134 at p 149. For present purposes it is sufficient for us to refer to the observations of Kitto J. in Reg. v. Trade Practices Tribunal; Ex parte Tasmanian Breweries Pty. Ltd. [1970] HCA 8; (1970) 123 CLR 361 at pp 374-375:

"Thus a judicial power involves, as a general

rule, a decision settling for the future, as

between defined persons or classes of

persons, a question as to the existence of a

right or obligation, so that an exercise of

the power creates a new charter by reference

to which that question is in future to be

decided as between those persons or classes

of persons. In other words, the process to

be followed must generally be an inquiry

concerning the law as it is and the facts as

they are, followed by an application of the

law as determined to the facts as determined;

and the end to be reached must be an act

which, so long as it stands, entitles and

obliges the persons between whom it

intervenes, to observance of the rights and

obligations that the application of law to

facts has shown to exist. It is right, I

think, to conclude from the cases on the

subject that a power which does not involve

such a process and lead to such an end needs

to possess some special compelling feature if

its inclusion in the category of judicial

power is to be justified."

22. In this case, the appellants suggested two features which they said justified the inclusion of the power to issue warrants under the State Act in the category of judicial power. First, the statute confers the power, not upon a judge, but upon the Supreme Court itself. Secondly, notice of an application for a warrant is required to be served on the Attorney-General pursuant to s.17. Neither of these features is compelling. The fact that a power is conferred upon a court suggests that the power is judicial in nature. But that is only one of the factors to be considered (Reg. v. Spicer; Ex parte Australian Builders' Labourers' Federation [1957] HCA 81; (1957) 100 CLR 277 at p 305; see also Farbenfabriken Bayer Aktiengesellschaft v. Bayer Pharma Pty. Ltd. [1959] HCA 32; (1959) 101 CLR 652 at pp 659-660) and it has limited significance when the function in question closely resembles those that have traditionally been classified as non-judicial. The power to issue a warrant under s.16 of the State Act stands in a similar position to the power to issue a summons, held to be a "matter of procedure" (Donohoe v. Chew Ying [1913] HCA 20; (1913) 16 CLR 364 at p 369) and most probably an "administrative or ministerial act": Electronic Rentals Pty. Ltd. v. Anderson [1971] HCA 13; (1971) 124 CLR 27 at p 39. See also Aston v. Irvine [1955] HCA 53; (1955) 92 CLR 353 at p 365.

23. The reasoning in Hilton v. Wells demands that undue emphasis not be placed upon the fact that the power is conferred upon the court. No doubt the legislature intended that the power would be exercised in a judicial manner by persons who are judges in order to allay any public misgivings about the issue of warrants under the State Act. But that has to do with the manner in which the power is exercised rather than with the nature of the power. Although the character of the repository of power is an important indicium of the nature of the power, it is not necessarily conclusive.

24. The requirement of service of notice upon the Attorney-General and not upon the person in relation to whom a warrant is sought indicates that the power is administrative rather than judicial. The very nature of the activities authorized by a warrant precludes notice to the individual whose privacy will be affected by action taken under the warrant. But the selection of a member of the executive government as the person to be served, whose role is to be afforded "an opportunity to be heard in relation to the granting of the warrant" (s.17(2)), strongly suggests that in issuing a warrant the judge is not engaged in a judicial determination of the rights of the parties.

25. However, the conclusion that the power to issue warrants pursuant to s.16 of the State Act is not judicial is not decisive of the question whether or not the act of issuing a warrant is itself judicial. A similar question arose in Hilton v. Wells. In that case the power to issue warrants pursuant to s.20 of the Telecommunications (Interception) Act was conceded to be administrative. Gibbs C.J., Wilson and Dawson JJ. (at pp 72-73) found sufficient indications in the statute to rebut any presumption that the power, conferred upon a judge, was conferred on the judge "as such". There the power was conferred upon a judge; here it is conferred upon the court. In the face of the indications that the issuing of a warrant pursuant to s.16 of the State Act is an administrative act, this distinction is insufficient for the appellants' purposes.

26. Although the administrative power to issue a warrant is in terms conferred upon the court rather than the several judges of the court, the exercise of the power is essentially administrative in nature. The warrant is the outcome of a complaint upon which the judge must bring his or her judicial mind to bear and decide on the material before him or her whether the warrant should issue. The judge is under a duty to act judicially and to that extent the issue of the warrant is a judicial act but it is not a "judicial act in the same sense as is an adjudication to determine the rights of parties", to use the words of Windeyer J. in Electronic Rentals, at p 39. It is not an order inter partes from which a party whose conversations may be overheard has a right of appeal. To adapt the language used in Hilton v. Wells, at p 73, under s.16 a judge makes no order and nothing that he or she does is enforced as an order of the court. Therefore, if a warrant is granted, its effect depends entirely upon the State Act.

27. Moreover, it may be that, on its true construction, the statute does not impose an obligation on a judge to perform the function of issuing warrants but gives him or her the option of consenting to do so or not: see Jones v. The Commonwealth (1987) 61 ALJR 348 at p 349; 71 ALR 497 at p 499. After all, exercise of the power may disqualify a judge from sitting in a case in which evidence is sought to be given of a conversation intercepted pursuant to the warrant.

28. There are, of course, many cases in which the issue of a warrant has been described as a judicial act: see, for example, the decisions referred to by Fox J. in Reg. v. Tillett; Ex parte Newton (1969) 14 FLR 101 at pp 118-119; Feldman, The Law Relating to Entry, Search and Seizure, (1986), par.4.07, n.1. But these cases, for the most part, are concerned with the availability of relief by way of certiorari and prohibition. Consequently they focus on the question whether the issuing authority had a duty to act judicially and, on occasions, judges have answered this question in the affirmative by stating that the issue of the warrant is a judicial act. The better view is that the issue of the warrant under s.16 is a step in the administrative process and is thus an administrative function. Granted that a judge considering an application for a warrant under s.16 is bound to act judicially, that is, in a just and fair manner, with judicial detachment, this circumstance is not conclusive, for the same is true of many administrative powers: Tasmanian Breweries, at p 373; Electronic Rentals, at p 39.

29. Although the appellants relied on the comments of Mason C.J. and Toohey J. in Murphy v. The Queen [1989] HCA 28; (1989) 167 CLR 94 (at pp 105-106) to support the view that a warrant issued under the State Act is a judicial order, the precise issue now under consideration was not argued in that case and we do not consider that the comments made in that case govern this issue.

30. Once it is accepted that the warrant is not a judicial order, it becomes an instrument made pursuant to a circumscribed statutory authority. Although on its face the warrant could be interpreted as purporting to authorize what would otherwise be a breach of Commonwealth law, it is necessary to construe the warrant by reference to the width of the enabling statutory provision. As soon as this is done, it is clear that the warrant can and must be construed so as not to do what the statute itself does not purport to do, namely, authorize a breach of s.219B of the Customs Act. The result is that the warrants in this case are wholly valid and the appeals must be dismissed.

31. The respondents did not seek to have the declarations of partial invalidity made by the Court of Appeal set aside, presumably because those declarations related only to the use of listening devices for the purposes of federal narcotics inquiries, for which federal warrants would be required in any event. There is therefore no basis for this Court to set aside the declarations.

32. It remains only to consider the respondents' applications for special leave to cross-appeal on the ground that s.219B of the Customs Act, when it refers to a person acting by arrangement with a member of the Australian Federal Police, does not include a member of a State police force acting as part of a joint federal/State task force. In the circumstances, the answer to that question has no bearing upon the outcome of the present proceedings and no relevance to the criminal proceedings against the appellants under State law. The case is therefore not appropriate for the grant of special leave.

33. The appeals and the applications for special leave to cross-appeal should all be dismissed with costs.

Applications for special leave to cross-appeal refused with costs.