Tax: A year away does not by itself end Australian residence
Under the tax law, someone domiciled in Australia stays resident unless the Commissioner is satisfied their permanent place of abode is outside Australia, and someone in Australia for more than half the year is resident unless their usual place of abode is overseas and they do not intend to live here. The ATO says you are generally resident if you go overseas temporarily and do not set up a permanent home in another country; you then declare income from Australia and overseas, with a possible offset for foreign tax paid.
More detail
If you stop being resident, assets other than taxable Australian property, such as many shares, are treated as sold at market value unless you choose to disregard this. The agreement between Australia and Vietnam was signed on 13 April 1992 and has been in force since 10 December 1992; Treasury lists it as modified by the Multilateral Instrument from 1 September 2023, and the ATO's synthesised text shows its residence, employment, independent-services and pensions articles in their original wording. If both countries treat you as resident, you are treated as resident of the country where you have a permanent home, or, if you have one in both or neither, where your personal and economic relations are closer. Pay for work done in Vietnam can be taxed there, unless all of these apply: you are in Vietnam no more than 183 days in the Vietnamese year of income, your employer is not a Vietnamese resident, the pay is not deducted in the profits of a Vietnamese permanent establishment or fixed base, and the pay is taxed in Australia. Income from professional or other independent services is taxable only in Australia unless you have a fixed base regularly available in Vietnam. Australia allows a credit for Vietnamese tax paid under the agreement, and pensions are taxable only where you are resident.
Sources: Federal Register of Legislation (Australian Government), Australian Taxation Office, Australian Treasury. Checked 15 October 2026.