As soon as we enter Australia, Centrelink and Medicare and ATO and AEC etc. will all be notified and Medicare coverage is immediate. Because I was always intending to go back I have maintained an address (family member) for all Government and Financial related matters. Despite long periods away I have maintained Medicare because as far as they are concerned I reside at that address. Not the same for CLink or ATO, but anything needed there is a matter of applying once a person gets back. I have also maintained my driving licence - on my last visit Any Citizen that has been away for a long time and not maintained an address, is immediately covered under Medicare the day they return. But they must apply and it can take a week or two for approval. Same for all the other Government services. Tip for all Expats returning to Australia who have been away a long time want to quickly re-activate Government and Private things in their lives. You need to find a long term rental place (6 months+) and get a signed Lease. Even if you are staying with a friend/family member get a Rental Lease document done (draft free online). You then take that Lease and your Passport to the Road Traffic authority and apply for a driving licence. You may need to start again and get a Leaners but that is OK - you just need that photo ID with your address on it. Those three documents (Passport, Licence, Lease) then give you everything you need to open a bank account, and then you can re-open all other Government services easily and quickly. You can then change your address with Govt etc. later to whatever you get as a long term place - they can all be done online these days.