As a "Yank", I'll shed some light as to how it works here in the States. Can't shed any opinion on what happens Down Under though. In the States, in order for an individual (private citizen or Law Enforcement Agency) to possess narcotics or explosives, they must have a license from the DEA (Drug Enforcement Administration) and/or the BATF (Bureau of Alcohol, Tobacco, and Fireams). Once they meet inspection (for example, a bunker must exist before any license for explosives is issued), the individual/agency may obtain and keep narcs/explosives. These individuals are subject to surprise inspections and detailed paperwork must be kept on the substances (ie. inventories, etc.). After September 11, 2001, my country went nuts for dogs. Before Sept. 11, everyone wanted narc dogs. Shortly afterward, everyone wanted bombers. I think it has about planed out now. We do not have a national K9 school that takes dogs from start to finish. We do not even have a national certification standard. The only thing we must show in court in order for our dog's "evidence" or "testimony" to be admitted is that the dog is trained and reliable. The way we achieve that standard is through the handler's training/experience (schools, certifications) and the dogs training/experience (training records, schools, certifications). What results as a handful of organizations dedicated to the pursuit of advanced K9 training and reliability such as USPCA, NAPWDA, IPWDA, NNDDA, etc. just to name a few. Most of the K9's on the street today in the US come from private trainers, with the exception of the military and a handful of the federal dogs. In fact, the dogs that guard our president come from a private individual- Ken Licklighter of Vohne Liche Kennels- probably the best in the business worldwide, especially when it comes to detection. There are several companies in the states that utilize their dogs to perform private sweeps for parents, schools, celebrities, and businesses. Even the music industry and large companies owning large venues used for sporting events or concerts employ these companies to sweep their venues prior to large events. Although a response by a properly trained and reliable K9 does constitute as probable cause as far as our Fourth Ammendment is concerned, the dog has to have the right to be there in the first place. In other words, I cannot not just bust into your house, sweep it with my dog, get a response, and be good in court. That is why many of your private companies here in the states are hired (thus invited) to sweep these areas and do so with permisson from their "clients". Their main selling point to their clients is they usually all have a confidentiallity clause in their contract. They sweep it, and once they get a response (as in the case with narc dogs), they notify their client, leave, and let them search it. As far as they are concerned, what the client chooses to do after that is up to them. Obviously, if enforcement was notified after all this occurs, I could see several issues with it when it comes to court, but most of the clients of these private companies offereing detection services hire them so they can deal with it in house anyway (with the exception of explosives of course!). I hope this helps.

Steve Austin acts as a trainer and adviser to the NSW Department of Corrective Services and NSW Department of Juvenile Justice Drug Detector Dog Units. But as Mark said no individual in Australia has access to real substances for detection work, permits apply to government departments only.