Besides the obvious wife/kids being in Australia = personal ties, ATO also considers the following to be reasonable points to be constituted as a tax resident:
- Australian Bank accounts, even with $0.01 in it.
- Superannuation
- Properties owned, regardless if it is as an investments or owner-occupied (not rented out)
- Any Australian Account e.g. commsec, vanguard australia, telstra/optus mobile, etc
- Postal address/P.O. box
And so forth. ATO is purposefully applying broad strokes to "ties" to Australia so that they can claim their share of taxes accordingly.
I have a mate whom is a miner, working offshore for BHP, and was audited by the ATO since he lives in Indonesia (wife/family) thus claimed he is a non-tax resident. He is originally from WA so got dinged for a house he owns in WA (which he intended to come back to) + his (Telstra) mobile plan that he never used but paid the smallest plan to keep so that he didn't lose his aussie number + his NAB bank account that had $1000 in it so that he has some cash to spend when he visits family. ATO told him that if he wanted to be considered a non-tax resident, he had to liquidate _and_ close everything he has in Australia to be considered a non-tax resident. Since he didn't do so, they considered he has every intention to return to Australia thus place undue burden on medicare & pension system, if applicable, thus had to pay the difference in tax he paid in Indonesia vs. working in Australia.