There are different types of professions that require that employees go for a police check so if you are going to be getting into one of these professions then you would definitely want to look for information on how you could go about getting a police check.
If you are from Australia then it would definitely have to happen through the Australian Federal police and this can usually be done online provided that you know how to proceed in the right direction. If you Google search the AFP, you will be able to find the official Australian Federal police website with information on everything you need to be able to gain access to a police check.
You will also be able to find other websites that can provide you with further details and more information about the Australian Federal police check as well as professions that require that you go for it which would put you in a better position to determine what the best course of action should be for you.
There are certain professions especially those related to volunteering whereby you may not be required to pay a fee for a police check so you should be looking for information about it by specifying what you are going for a police check for in order to be provided with appropriate information.