Firstly you will need to determine if your income is taxable in Australia or/and in the country to which you services are being performed.
Earnings are considered foreign when the work is performed overseas.
Secondly, depending on the length of time spent outside of Australia you will need to consider whether you are still considered to be an Australian Tax Resident.
Your tax residency is fundamental to determine who has taxing rights over your worldwide income with particular reference to the salary being paid to you.
Your residency is often a significant issue, as residents of Australia are subject to income tax on their worldwide income and non-residents are only taxable on their Australian sourced income subject to the exempted income provisions.
It is possible to be a dual resident with the overseas country and Australia. Should this be the case you would need to consider which country has overriding residency which is commonly referred to as treaty residency as it is the conditions set in the double taxation agreement which would determine this deciding point.
Once your residency position has been determined you can better understand who has taxing rights over your income along with your tax reporting obligations in both countries.