You might find it necessary to go for an individual national crime check report which is all about being cleared by the police to be able to take up certain job types which depends upon the nature of your profession.
If you are going to be working in the aviation industry then you would understand how sensitive the whole situation has become over the past decade or so which means anyone looking to work in such industries would be required to get a police clearance before they are able to do anything.
So whether you are looking to work at an airport or anywhere else it would be necessary for you to have police clearance before you can even be employed. An Australian Federal police check can be applied for online and a report is usually valid for a 12 month period and you can keep applying for new reports each time you have a need for it.
Your employer may just require it once depending upon what their policies may be as they might even ask that you go for a new police check periodically. You can get detailed information online on a national crime check from specialist websites that are of a legal nature as you should be aware of everything before deciding to go for something along these lines.