I was just looking at the Unlock Information Hub about travel to Australia. It mentions that you will be ineligible for a basic tourist visa if your have "one or more sentences, or if your sentence was 12 or more months". The examples it uses to illustrate this are custodial sentences (e.g. you are given a 12 month sentence, but only serve 6 months, you are still ineligible). However, does a community order constitute a "sentence"? The Information Hub and Australian visa page both give the impression that this is referring to custodial and/or suspended sentences.
I should point out, that even if you don't meet the criteria for a basic visa based on the above, you can still apply via another route (see info hub for more on this).