Getting an individual police check is easier now as it can easily be done online which is something that was not possible in the past. This is something that is required for people that work in certain professions so the first thing that you will want to do is check whether you are required to go for a police check.
It would also be available for a small fee unless you are in a profession that is not for profit such as an NGO or a volunteering job in which case, you may be able to qualify for a free police check from the AFP in Australia. You can find information about eligibility criteria as well as how much it would cost for you to get an AFP police check online through several websites.
You can find websites that discuss about police checks through Google by searching for appropriate keywords as there are numerous points that you will want to be aware of before you could go ahead and file your application for a police check. An AFP individual police check certificate would usually be valid for 1 year so if you already got one in the past one year or so then it should be good enough unless it has already expired in which case you will have to apply for a new one.