A majority of the High Court has dismissed appeal from the decision of the NSWCA relating to the powers of the Independent Commission against Corruption (ICAC) under the Independent Commission against Corruption Act 1988 (NSW). Following a motor vehicle accident, the first and second respondents allegedly advised the third respondent to pretend to have chest pains so as to prevent police officers from obtaining evidence of the third respondent’s blood alcohol level at the scene of the accident. ICAC commenced a public inquiry under s 31 of the ICAC Act. The respondents challenged that inquiry on the basis that it was beyond ICAC’s powers, namely to investigate allegations of corrupt conduct, defined under s 8 as including conduct that ‘adversely affects, or that could adversely affect’ the honest and impartial exercise of official functions by any public official. A majority of the NSWCA interpreted s 8(2) as relating only to conduct that ‘has the capacity to compromise the integrity of public administration’ in the sense of leading to the corruption of an official, and held that the alleged conduct was beyond ICAC’s investigatory powers. Bathurst CJ (in dissent) held that it extended to conduct within the ordinary meaning of the word, and held that the inquiry was within power.

The majority (French CJ, Hayne, Kiefel and Nettle JJ) held that of the two possible meanings of ‘adversely affect’ — either relating to the ‘probity of the exercise of an official function by a public official’ or to the ‘efficacy of the exercise of an official function by a public official’ — the probity definition is to be preferred: it accords with the ordinary understanding of corruption in public administration and the purposes of the ICAC Act, whereas the efficacy meaning would expand the meaning to a range of offences that are unrelated to either corruption or the purposes of the ICAC Act, and would expand ICAC’s powers well beyond its purpose as an anti-corruption body ([2]–[3]). The majority was critical of both approaches taken by the NSWCA. It rejected the plain and ordinary meaning approach taken by Bathurst CJ on the basis that it assumed the broadest possible meaning and did not account for the statutory context (see [32]ff), and also stated that the NSWCA majority’s approach was open to circularity because it assumed the purpose of the act and then preferred a meaning of ‘adversely affect’ that was more consistent with those assumed purposes (see [33]–[34]). Instead, the majority outlined that the preferred approach was to examine relative consistency (at [35]):

It is impossible to identify the purpose of the ICAC Act (and, therefore, impossible to establish a major premise against which to compare the relative consistencies of the competing constructions of ss 8 and 9) without reference to the scope of operation of the Act as defined by ss 8 and 9. For the same reason, it is not open to express a conclusion as to the meaning of “adversely affect” in s 8(2) in terms of absolute validity. The best that can be done is to reason in terms of relative consistency – internal logical consistency and overall consistency in accordance with the principles of statutory interpretation adumbrated in Project Blue Sky [1998] HCA 28 – to determine which of the two competing constructions of “adversely affect” is more harmonious overall.

After reviewing the text, structure and context of the ICAC Act (see [36]ff), the majority emphasised that the symmetry of the structure of s 8 meant that ‘adversely affect’ in s 8(2) means ‘to adversely affect the exercise of an official function by a public official in such a way that the exercise constitutes or involves conduct of the kind identified in s 8(1)(b)–(d)’, that is, dishonest or partial exercise of a public power, breach of public trust or the misuse of information or materials in the course of official functions ([44]–[45]), which go to defining improbity in public administration at which the ICAC Act is aimed ([46] and see following). The majority stated that the probity reading was reinforced by the many possible offences under the efficacy meaning that would range far beyond corruption (see examples at [52]), and held that

It is not likely that an Act which is avowedly directed to investigating, exposing and preventing corruption affecting public authorities – and for which the justification for the conferral of extraordinary powers on ICAC was said to be the difficulty of discovering and exposing corruption in the nature of a consensual crime of which there is no obvious victim willing to complain – should have the purpose or effect of extending the reach of ICAC to a broad array of crimes having nothing to do with corruption in public administration apart from such direct or indirect effect as they might conceivably have upon the efficaciousness of the honest and impartial exercise of official functions by public officials.

The majority also dismissed a final possible construction under which the clause ‘and which could involve’ limited and defined the phrase ‘the exercise of official functions’ rather than ‘conduct’ (see [65]–[70]). Gageler J, dissenting, preferred the efficacy construction on the basis that the provision only requires that the conduct have the potential to limit or prevent the proper exercise of official functions by the public official (see [81]ff).