There is/was a DNC register here, but there are/were so many exceptions I never bothered registering my now defunct landline number. I'm not sure if you can register mobile numbers - at one time you couldn't.
Interestingly the two spam SMS messages I was getting every day have ceased - maybe they were coming from here
I only get a few easy to spot spam messages on my mobile devices. I also get messages from my telco to say that nnnn nnn nnn just called but didn't leave a message. Not sure how that works - the phone didn't ring.
Because I live in a district that's been held by Labor on wide margins since federation I don't get any unsolicited calls, emails, or messages from political actors.