9.118   A wide range of Commonwealth laws have been enacted with retrospective operation, including criminal, taxation and migration laws. However, retrospective criminal offences are rare and the areas of most recent controversy and comment concern taxation and migration laws.

9.119   Taxation law provides numerous examples of laws with retrospective operation. Taxation measures are often enacted with some retrospective operation and it is a ‘constant fact that a change to tax law is announced and applied to transactions that took place before the relevant legislation commences’.[132] There is widespread acceptance of retrospective taxation laws that commence from the date of the announcement, where the period of retrospectivity is short and the announcement is clear.

9.120   Taxation laws that provide for lengthy periods of retrospectivity might be reviewed to ensure that these laws do not unjustifiably change legal rights and obligations.

9.121   There are concerns that the retrospective operation of some of Australia’s migration laws has not been sufficiently justified, including changes to the protection visa regime, the people smuggling offences and the character test. Some of the changes have very significant consequences for the people affected, and it is not clear that retrospective operation is necessary to achieve the objectives of the legislation. However, these laws have been subject to inquiries by the Senate Standing Committee on Legal and Constitutional Affairs in 2011 and 2014. The ALRC is interested in comment as to whether these laws should be subject to further review.