No there is no reliable list to check as spam callers do not use real numbers, they obscure them or fake them and change them often. They only look like Australian numbers. No your Telco cannot police them, in part because of the fake numbers. There is no simple way to create an accurate black list and I doubt they are much interested in trying. The DNC register is no use as the spammers just ignore it, even though they may look like Australian most are overseas call centres and are out of jurisdiction.
This topic has been brought up before, there is no easy and comprehensive solution to the problem.Most people who have the problem seem to use some variation on what you are doing. It works when the caller is known to you (on your white list) and the reply is not urgent but the problem of missing a genuine caller unknown to you or missing something urgent is still there. Ignoring those who conceal their number doesn’t work either. I have friends who show up as PRIVATE NAME PRIVATE NUMBER. I have also got genuine calls from institutions such as hospitals that do the same. About the only good news is that spammers rarely leave messages and those you want to speak to do so you don’t waste much time going through the message list looking for those to return.
Phone spamming, including con jobs, is like email spam. As the cost of initiating such contacts is almost zero making thousands of contacts on the chance of getting some money out of a small percentage of them is a viable business model.