Is Evidence Collected Illegally Always Inadmissible?

It is extremely important that evidence for prosecutions is collected legally. If site inspections are not conducted in a legal manner, any evidence that is collected may be deemed inadmissible by a Court – which will usually mean the prosecution will fail.

However, in the event that evidence is unintentionally collected illegally there is a possibility that evidence can be admissible.  This will need to be determined on a case by case basis.

What if we have evidence but it was collected not in accordance with the entry provision we should have used?

The most likely way in which evidence has been collected illegally ( when dealing with local governments)  is where a property has been entered when the officer entering the property either does not have the appropriate authorisation or has not complied with the required notice provisions.

If the property has been entered in a way which does not met the requirements of the appropriate Act – and you need the results of that inspection to be admitted into evidence,  there is a case which you can use called Bunning v Cross [1978] 141 CLR 54 which outlines an option where illegally obtained evidence can be included in evidence – that of “public interest outweighing unfairness”.

“17  This question of the competition of the public interest in conviction with the unfairness to the applicant in connection with the taking of the test, he could properly have come, was that there was no unfairness to the applicant in the circumstances and manner of the obtaining of the evidence as to the alcoholic content of his blood. There was nothing whatever to outbalance the public interest in the enforcement of the law.

18 I have had the advantage of reading the reasons for judgement prepared by my brother Stephen and Aickin. I agree entirely with their observations on the proper principles to be followed in exercising a discretion to exclude admissible evidence because of the circumstances or manner in which it was obtained or came into existence…” Barwick CJ

Stephen and Aickin JJ outline a number of factors to be considered when attempting to decide whether the public interest outweighs unfairness. These are:

  • no deliberate disregard of the law (by the evidence collector) should be involved;
  • whether the nature of the disregard of the law (ie the way in which the evidence was collected) affects the cogency (or the clearness or lucidity) of the evidence in question. Most of the time cogency will play a smaller role – if at all if the illegality of the collection of the evidence was reckless or intentional;
  • how easy it would have been to collect the evidence legally;
  • the comparative seriousness of the offence versus the seriousness of the unlawful conduct of the local government; and
  • the intent of the Parliament in limiting the ways in which evidence may be collected.

This will be determined on a case by case basis and it will be difficult to predict the outcome of the matter.


Always enter properties using the correct Act and in accordance with the provisions of that Act. Make sure your authorisations are current and correct. Relying on the case of Bunnings v Cross [1978] 141 CLR 54 to render evidence admissible is risky and may not produce the desired result.

For more information on this update or any other Local Government matter please contact Anne Wood on (08) 9321 3755.

The information published in this paper is of a general nature and should not be construed as legal advice. Whilst we aim to provide timely, relevant and accurate information, the law may change and circumstances may differ. You should not therefore act in reliance on it without first obtaining specific legal advice.