This is a great question. I don't know the market in Australia, but I do understand how this is done in the US and europe. I would not be surprised to find that Australia is similar. There is a good reason you don't find the information on the internet...
In the US, there are multiple requirments.
FCC will be the first we discuss. The FCC has requirments for conducted and radiated emmissions. Conducted emmissions are the RF energy transmitted via a line cord, back into the AC power system. There is a testing method called out by the FCC. The testing must be performed by an entity, that goes through a qualification process. There are many vendors that can do this testing for you. Google "Conducted Emissions Testing", and you will find many. The big names that do this are UL and ETL (Intertek). Radiated emissions testing is required if a device has certain components that may produce RF emmissions. The FCC site gives rules on what devices must be tested. Again there are qualified vendors who do the testing. Google for them, but UL and ETL do this work.
Next is safety. There are not necessarily requirments for safety for all devices. But, if you produce an unsafe device, and someone decides to sue, you can be held liable. Most companies get around this by complying to industry standards. Also, certain devices, like those connected to the AC power distribution system, are often required to meet certain standards. The US "incorporates by reference" these standards into the rules (laws). Right now there are some people that are challenging this "incorporation by reference". The issue is that standards bodies have used their manpower and experience to develop the standards, so to get access, you must pay. The contention is that this produces "secret laws" where you must pay to find out what the laws are! I expect that we are going to see some changes in the standards area in the years to come, as this has some basic problems. The standards bodies need to get paid for their work, but the people need to have access to the rules / laws. This makes meeting the rules rather difficult.
In a more practical sense, the best way to approach this, is to work with a company like UL or Intertek and have them review your design and give you a quote on what standards you would need to meet, and their fee for testing your design to those standards. Their quote will then give you the list of standards you will need to buy, and understand for your device. The good news, is that by going this route, when your design gets a safety mark, this ensures your design has met certain industry standard practices, and typically the safety agency will represent in court that your design meets those standards, which should go very far toward reducing any liability you may have.
As you can see, there are a number of hurdles. By getting rid of designing the AC power supply, and choosing a device that meets conducted and radiated emissions, and carries such approval, you get rid of those testing requirments.
Then your device may need FCC testing. You can determine if this is needed by looking at the requirments for your country, for radiated emissions, and RF transmitters / receivers. These rules in the US are open, and for some devices no testing is required. For many devices, testing is not that expensive, and may be a couple thousand dollars.
Safety is a bit more problematic. If your device requires approval, as some building codes or laws reference standards, then you either buy the standards, and hope you don't misunderstand or misapply them, or you get someone else to certify your design. If not stadards are required by law, you may still want the protection of the standards, in which case you buy them or work with a testing house, or you decide to incorporate so that your personal assets are protected, and only the corporate assets are at state, should a lawsuit occur.
Anyway, this is only part of getting a product to market. Don't forget paying for material, shipping, tariffs, production, legal matters with who owns what at different points in the process, so that if something is damaged or lost, who is liable?
The good news is that if you have an idea, and can get some products to work, there are contract manufacturers that can either do or help with all this.