39 Section 136 of the Act contains no indication as to whether the legislature intended the presumption to be displaced. The provision forms part of a statutory regime which is concerned with the entry and inspection powers of authorised officers or representatives defined under s 76 of the 2000 Act. Section 76 appears in Division 3 of Part 5. That Part contains a number of offence provisions, which, like s 136, deal with offences relating to the exercise of official functions or duties of an authorised representative. Section 84, for example, provides that a person must not "without reasonable excuse" refuse or fail to comply with a requirement made by an authorised representative. Section 92 provides that a person who "without reasonable excuse" fails to comply with a requirement imposed by an improvement notice commits an offence. Section 94, in similar terms to s 92, makes it an offence to "without reasonable excuse" fail to comply with a requirement imposed by a prohibition notice. The absence of the words "without reasonable excuse" in s 136 raises the proposition that no reasonable excuse will avail a defendant at premises who obstructs an authorised representative attending those premises. If so, this would lead (in the absence of some other defence or excuse being available), as Gibbs CJ in He Kaw Teh pointed out in the context of s 233B(1)(b) of the Customs Act, to an absurdly draconian result. In this circumstance, a person who unwittingly hindered or obstructed an authorised representative who was exercising an official function under the 2000 Act, could be found guilty and liable to pay a substantial fine.
40 We consider that the words "hinder, obstruct, or impede" as they appear in s136, are not of themselves indicative of a criminal act. An owner or occupier of premises has a right (ordinarily) to hinder or obstruct persons entering those premises without permission or other kind of authorisation: (Federation of Air Pilots v Australian Airlines Limited (1991) 36 IR 194 at 207, 208 per Gray J). The offence, with which s 136 is concerned, places a focus on the conduct of a defendant in circumstances where authorised representatives enter premises, occupied by the defendant, for the purpose of exercising an official function under the 2000 Act.
41 Discerning the subject matter of s 136 also requires a consideration of the inter-relationship between that provision and other provisions of the 2000 Act. Under s77, an authorised representative is granted the power to enter any premises if he has reason to believe it is a place of work where members of an industrial organisation, or persons eligible to be members work, for the purpose of investigating any suspected breach of the 2000 Act. Under s 78, the authorised representative may enter the premises without notice but if he does so, the occupier of the premises must be notified as soon as reasonably practicable of the entry. Under s 78(2), there are exceptions to this latter requirement where notification of entry would defeat the purpose for which entry was effected or would cause unreasonable delay in a case of urgency prior to the occupier being notified in advance. Under s 79, the power to enter premises may not be exercised unless the authorised representative is in possession of an authority issued under Chapter 5, Part 7 of the Industrial Relations Act. In addition, under s 79(2) entry may only be effected at a reasonable time in daylight hours and when work is carried on or usually carried on at the premises.
42 Sections 77 to 79 are intended to be enabling or beneficial provisions (cf Federation of Air Pilots at 208). The rights conferred on an authorised representative under the provisions are significant and play an important role in ensuring the safety of members of an industrial organisation (and those eligible to be members) at work. They also play a vital role in facilitating the investigation and enforcement of suspected breaches of occupational health and safety law. Section 136, on the other hand, creates a criminal offence which is punishable by a fine. The two sets of provisions, although exhibiting a degree of tension, nevertheless operate, in combination, to fulfill an important function.
43 In Federation of Air Pilots, Gray J concluded that similar provisions in combination operated to remove the presumption that an occupier of premises could hinder or obstruct a person entering those premises for the purpose of carrying out an inspection. His Honour found that the purpose of one provision (which was to assist with the enforcement of awards by authorising an officer of a union to enter premises for the purposes of inspection or interview) pointed towards the related offence provision being one of strict liability, and that the nature of the intrusion into what would otherwise be the rights of an employer pointed to a requirement of some mental element.
44 We would similarly conclude in considering provisions of the Industrial Relations Act in relation to the combined operation of ss 77 to 79 and s 136 of the 2000 Act. Given that important rights of an owner or occupier of premises are subject to the provisions of ss 77 to 79, and that the owner or occupier becomes criminally liable for a breach of s 136, we are of the view that some mental element is required in order to make out the breach.
45 As to the third matter referred to by Gibbs CJ, it seems to us that there would be little utility in convicting a person under s 136 who hinders or obstructs an authorised representative in the exercise of his official functions, but who holds a genuine and reasonable belief that the authorised representative is not properly authorised to enter the premises or is not at those premises for the purpose of exercising an official function under the 2000 Act. This consideration, in our view, also serves to provide an indication that the offence under s 136 requires some form of mental element, such as the holding of an honest and reasonable but mistaken belief, that the person entering the premises is either not properly authorised or not entering for an official purpose under the Act.
46 We are also of the view, although we have not been asked to decide the point, that the offence under s 136 does not fall into the first category of offences identified in Wampfler. An owner or occupier of premises as we have earlier observed ordinarily has a right to hinder or obstruct persons entering their premise. It would be difficult therefore, to prove, directly or inferentially, the state of mind of a defendant who obstructed or hindered an authorised official in the exercise of his or her official function under the 2000 Act: Federation of Air Pilots at 208. In undertaking an analysis of whether a similar offence provision under consideration in Federation of Air Pilots fell into the first category, Gray J distinguished the case of assault on a police officer, where the assault itself is an offence, (see also Environment Protection Authority v N (1992) 26 NSWLR 352 at 356 per Hunt CJ at CL). As we earlier observed, conduct amounting to obstruct or hinder on the part of an owner or occupier of premises does not, of itself, constitute conduct which is criminal under s 136. Under the provision, it is the hindering or obstruction of the authorised representative exercising an official function which is the gravamen of the offence.
47 A further consideration raised during oral hearing on the appeal concerns the impact of the defences under s 28 of the 2000 Act on a construction of s 136(1)(a) as an offence of strict liability. Section 28 provides:
28 It is a defence to any proceedings against a person for an offence against a provision of this Act or the regulations if the person proves that:
(a) it was not reasonably practicable for the person to comply with the provision, or
(b) the commission of the offence was due to causes over which the person had no control and against the happening of which it was impracticable for the person to make provision.
48 Section 28 operates to provide two defences to offences under the 2000 Act. In terms, it purports to apply to all offence provisions in the 2000 Act. We have earlier referred to a number of offence provisions contained in the 2000 Act which expressly provide for the defence of "without reasonable excuse". Other offence provisions contained within the 2000 Act expressly import mens rea as an element of those offences. Section 24(1)(a), for example, prohibits conduct of a person who intentionally hinders or obstructs the giving or receiving of aid to an injured worker.
49 Even if the offence provisions set out in the 2000 Act contained no express indication that mens rea is a constituent element, it does not follow that the defences in s 28 are otherwise available or that those other offence provisions are offences of absolute liability. In this regard, we would agree with the observation made by Black CJ in Chief of the General Staff v Stuart (1995) 58 FCR 299 at 305 that:
As He Kaw Teh shows, the existence of a statutory defence does not mean that the presumption that mens rea must be proved is necessarily displaced with respect to the offence for which such a defence is provided.
50 In Environment Protection Authority v N, the legislation under consideration (Environmental Offences and Penalties Act 1989), provided a defence under s 7 in identical terms to s 28(b) of the 2000 Act. In the judgment, Hunt CJ at CL (with whom Enderby and Allen JJ agreed) held that s 5(1) of the Environmental Offences and Penalties Act had not displaced the common law presumption of mens rea. With regard to the defence provided under s 7, Hunt CJ at CL, described the provision as a blanket provision, and one which often poses a problem of a logical nature.
51 It is not necessary, to our consideration of this present issue, to offer comment on the nature and application of the defence provided under s 28(b) of the 2000 Act which is in identical terms to s 7.
52 The application of the s 28 defences raises a logical difficulty in utilising those defences against an offence under s 136 which has been proved by the prosecution. Section 28(a) is concerned with the concept of reasonable foreseeability, which is decided on an objective basis, that is, whether the particular act constituting the offence provision was foreseeable to the reasonable person in the position of the defendant, see Department of Mineral Resources of NSW (McKensey) v Kembla Coal and Coke Pty Ltd (1999) 92 IR 8 at 27. Section 28(b) refers to causes, rather than acts, over which a defendant has no control. Neither defence clearly deals with a defendant who refuses entry to premises, for example, because he mistakenly believes that the authorised official is not properly authorised or is not attending those premises in the exercise of his official functions.
53 The words "hinder" and "obstruct" carry with them the notion of awareness (of the act of obstructing or hindering). The act of obstructing (or hindering), as we have already observed, does not, of itself, constitute criminal conduct. There must exist a connection between the concept of obstruction or hindrance, and the nature of the activity being obstructed or hindered before a defendant may be held criminally liable: Curran v Thomas Borthwick & Sons (Pacific) Ltd (No 1) (1990) 33 IR 6 at 20, per Gray J.
54 In that judgment, Gray J considered some examples where an obstruction or hindrance may constitute a criminal act and where it may not. The examples, as his Honour noted, recognise the necessary connection between the act (of obstructing and hindering) and the nature of the activity obstructed or hindered. One example concerned users of a highway. Since the space occupied on a highway cannot be used simultaneously, occupation of that particular space by a user is technically an obstruction. But since the legitimate purpose of the highway is passage and re-passage, the user of the highway occupying the space for that legitimate purpose cannot be said to be obstructing it: Schubert and Another v Lee (1946) 71 CLR 589 at 594 to 595.
55 By way of analogy, in the context of s 136, a refusal to provide the key to a locked cabinet containing documents of interest to the authorised official exercising official functions under the 2000 Act may not constitute an obstruction or hindrance of that officer if the reason for the refusal was a lost key to the cabinet. A defendant may adduce evidence to establish the fact of the lost key but that evidence would be relevant to the issue of liability. In such circumstances the defences under s 28 would have no work to do.
56 We would add, although not relevant to the disposition of the appeal, that in our view a "defence" of honest and reasonable mistake of fact is available to corporate defendants as well as natural defendants. The issue assumes relevance in the context of an offence under s 136 which carries penalties against corporations as well as individuals. Whether a corporation may be able to rely on the "defence" depends upon whether the person operating under the mistaken belief was the "directing mind and will" of the corporation: see for discussion of the phrase, Presidential Security Services of Australia Pty Ltd v Brilley (2008) 67 ACSR 692 per Ipp JA (with whom Allsop P and Beazley JA agreed) at [115], [140] and [155]. The issue falls to be decided by reference to the facts and circumstances of each case. Presidential Security Services of Australia provides a useful illustration of when the acts, conduct or state of mind of an individual may be attributed to a corporate defendant, such that liability for those acts, conduct, or state of mind attaches to the corporate defendant (at [156] - [158]).
57 We turn now to consider the two grounds of appeal.