When importing any item that uses power from another country there are potential issues that you need to be aware of. Issues are centered around voltage and plug types.
Items That Use Batteries
If your item uses batteries (such as AA, C, D, 9V, etc), there is not problem as typical battery sizes are the same all over the world.
Includes items that uses mains power is used to recharge batteries
If an item runs off mains supply, or its battery needs to be recharged from the mains occasionally, you may have a problem.
Australian electricity is mostly 240 Volts but North America uses 110 Volts. Europe uses 220 Volts which is similar to Australia as is most of the world. Another difference between Australia and USA is that Australia uses 50Hz whilst North America uses 60Hz.
So if your item (or its battery recharger) plugs directly into the mains, check to see if it’s compatible. Some items (for example, some hair dryers) can be switched between voltages.
Please note that a 110-volt item will burn out if plugged into 240 Volt but a A 240 Volt gadget should not burn out on 110 Volt, but it won’t run correctly.)
Most items that use a power pack or power brick style of power supply can be used with any voltage, but not all plug packs are “universal” — some are good only with one voltage. Check yours to be sure.
With these power pack/brick style of power supply that can use 240 volts it is often just a case of getting a new power cord with an Australian plug.
These examples show the typical connectors for these types of power brick/pack style of power supplies
Most computers also can handle both 110v and 220v and only require a new power cord with an Australian plug.
With items that can handle both 110v and 240v after you use a new power cord or a plug adapter these items should be safe to use in Australia.
Many people have old power cords around the house that can be re-tasked to your new purchase however you can also buy them at most computer stores, Harvey Norman, Dick Smiths or Tandy. Plug adapters can be purchased in even more locations and you can even buy it though Amazon.
But What if your item cannot handle 240v?
For items that cannot handle the Australian 240v mains power as it has only been designed for the USA market. then transformers are available. You can purchase them here in Australia or through Amazon. The size of the transformer required will depend on the power draw of the item itself so insure you research exactly what your power requirements are before purchasing.
Transformers for low power usage items are quite small and are often used by international travellers. Transformers for items with much higher power requirements are quite large, heavy, expensive, and heat up noticeably.