I suspect the following applies to all states but I can only speak with confidence in regard to Victoria:

If one is a permanent nomad (itinerant) as opposed to someone doing a tour of Oz for a few years then one may apply to the Australian Electoral Commission (AEC) to be marked on the electoral roll as itinerant. This status removes the requirement to vote at elections.

States also hold their own electoral rolls but mainly rely upon the AEC for their data. As people eligible for jury service are drawn from the state electoral roll I was hopeful that if I registered as "itinerant" I would not be eligible for jury service - not so.

It seems that whatever one's living status one remains on the electoral roll but is simple marked as "itinerant" or "silent" etc and therefore may be selected for jury service. Should that be the case it will then be necessary to either do it or try to persuade the jury service why you should not.

An awful lot of people fought and died in order I may be tried by "twelve good men and true" and I hasten to point out I would be happy to do jury service but parking a caravan near the Melbourne law courts could be an issue... and I imagine camp fires are right out? :)

Above info. courtesy of the AEC who were also interested to know what the situation was when I asked, as they were not sure either :)

Edit:

I should add that when marked as itinerant one still has the *option* to vote.