The use of surveillance technologies other than the interception of telecommunications is governed in each State and Territory by their own legislation. One aspect in common with all Acts is that the use of a surveillance device, without a justifying factor in operation, is a crime. This means that the prosecution is encumbered with the normal evidentiary burdens of a criminal trial. Justifying factors include the user being a party to the activity or conversation and/or having the consent of the other parties, or some legitimate and lawful interest in the matter.

 

Each jurisdiction will be considered separately, after an examination of points of confluence where the law is similar in different States and Territories. Confluences occur due to similarity in wording, and due to the persuasive authority of parallel courts. We also examine a few much older case law rules that have relevant effects.

 

The material presented hereunder is to serve as a guide when reading the State and Territory specific studies which appear later in this study. To save space we review hereunder some areas where the law is found to be the same between the Australian jurisdictions. After this we will look at the legislation of each jurisdiction separately.

 

The Principle of Persuasive Authority

Firstly, for the layman, a note on how courts in different jurisdictions influence each other. Certain legal principles are shared in common between the States and Territories due to similarity in the wording of statutes and due to the wider effect of common law. For this reason, and because of some concepts being shared between different jurisdictions’ Acts, court rulings on the meaning of the wording of different Acts have persuasive authority across borders. The reader should be aware, however, that where judgements are criticised as unconvincing, this is principally for the benefit of States and Territories other than those in which the judgments were given, and for those ready and able to take matters to appeal. Subsequent decisions of the same court and lower courts are bound to follow and apply prior decisions.

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