Protections from statutory encroachment

Australian Constitution

13.35  There is no express or implied prohibition on the making of retrospective laws in the Australian Constitution. In R v Kidman, the High Court found that the Commonwealth Parliament had the power to make laws with retrospective effect.^[35] In that case, which concerned a retrospective criminal law, Higgins J said:

There are plenty of passages that can be cited showing the inexpediency, and the injustice, in most cases, of legislating for the past, of interfering with vested rights, and of making acts unlawful which were lawful when done; but these passages do not raise any doubt as to the power of the Legislature to pass retroactive legislation, if it sees fit.^[36]

13.36  Similarly, in Mutual Pools & Staff Pty Ltd v Commonwealth, Mason CJ said:

The power of the Parliament to pass retrospective criminal legislation is beyond doubt. Similarly, the federal Parliament can retrospectively validate unlawful conduct either absolutely or conditionally if that conduct is a matter falling within a federal head of power. ^[37]

13.37  The Constitution also permits retrospective laws that affect rights in issue in pending litigation.^[38]

13.38  The power of the Australian Parliament to create a criminal offence with retrospective application has been affirmed in a number of cases, and is discussed in Polyukovich.^[39] In that case, McHugh J said that ‘Kidman was correctly decided’^[40] and that

numerous Commonwealth statutes, most of them civil statutes, have been enacted on the assumption that the Parliament of the Commonwealth has power to pass laws having a retrospective operation. Since Kidman, the validity of their retrospective operation has not been challenged. And I can see no distinction between the retrospective operation of a civil enactment and a criminal enactment.^[41]

13.39  However, retrospective laws that amount to the exercise of judicial power by the legislature, or interfere with the exercise of judicial power by Ch III courts, may be unconstitutional. A bill of attainder is a statute that finds ‘a specific person or specific persons guilty of an offence constituted by past conduct and impos[es] punishment in respect of that offence’.^[42] In Polyukhvich, the High Court said that such a statute would contravene Ch III of the Constitution which requires judicial powers to be exercised by courts, and not the legislature.^[43] Emeritus Professor Suri Ratnapala noted that the ‘common theme’ in the judgments was that

a law that retrospectively makes an act punishable as a crime does not offend the separation doctrine, provided it is general and not directed at specific individuals.^[44]

13.40  Thus, bills of attainder are prohibited not because they are retrospective, but because determining the guilt or innocence of an individual amounts to an exercise of judicial power.^[45]

13.41  Similarly, a retrospective law that interferes with the functions of the judiciary, such as by altering the law of evidence or removing discretion regarding sentencing of particular persons, may be unconstitutional because of Ch III.^[46] Again, the concern is not the retrospective nature of the law, but its interference with the judicial process.^[47]

Principle of legality

13.42  The principle of legality provides some protection from retrospective laws.^[48] When interpreting a statute, courts will presume that Parliament did not intend to create offences with retrospective application unless this intention was made unambiguously clear.^[49] With regard to civil laws, courts will presume that Parliament did not intend to retrospectively change legal rights and obligations. For example, in Maxwell v Murphy, Dixon CJ said:

the general rule of the common law is that a statute changing the law ought not, unless the intention appears with reasonable certainty, to be understood as applying to facts or events that have already occurred in such a way as to confer or impose or otherwise affect rights or liabilities which the law had defined by reference to past events.^[50]

13.43  However, this presumption does not apply to procedural (as opposed to substantive) changes to the application of the law.^[51]

International law

13.44  The principle that a person should not be prosecuted for conduct that was not an offence at the time the conduct was committed is a rule of customary international law.^[52] It is embodied in the maxim nullem crimen sine lege, nulla poena sine lege.^[53] It has been incorporated into art 15 of the International Covenant on Civil and Political Rights (ICCPR):

1. No one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence, under national or international law, at the time when it was committed. Nor shall a heavier penalty be imposed than the one that was applicable at the time when the criminal offence was committed. If, subsequent to the commission of the offence, provision is made by law for the imposition of the lighter penalty, the offender shall benefit thereby.

2. Nothing in this article shall prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of law recognized by the community of nations.

13.45  International instruments cannot be used to ‘override clear and valid provisions of Australian national law’.^[54] However, where a statute is ambiguous, courts will generally favour a construction that accords with Australia’s international obligations.^[55]

Bills of rights

13.46  In other countries, bills of rights or human rights statutes provide some protection from retrospective laws. There are prohibitions on the creation of offences that apply retrospectively in the United States,^[56] the United Kingdom,^[57] Canada^[58] and New Zealand.^[59] For example, the Canadian Charter of Rights and Freedoms provides that any person charged with an offence has the right

not to be found guilty on account of any act or omission unless, at the time of the act or omission, it constituted an offence under Canadian or international law or was criminal according to the general principles of law recognized by the community of nations.^[60]

13.47  The right not to be charged with a retrospective offence is also protected in the Victorian and ACT human rights statutes.^[61]