If you leave
Australia permanently you are not treated as an Australian resident for tax purposes from the date of your departure.
If your status has changed from resident to non-resident during the income year, answer 'Yes' to the question 'Are you an Australian resident?' on your tax return. This ensures you are taxed at resident rates for the tax year. Your non-residency for part of the year is taken into account by a reduction in your tax-free threshold. You are entitled to a pro-rata tax-free threshold for the number of months you are an Australian resident.
Foreign/non-residents of Australia are not required to pay the Medicare levy, so you can claim the number of days that you are not an Australian resident during a tax year as exempt days in your tax return.
From the date you cease to be an Australian resident, there is no need to disclose your foreign source income in your tax return.
I am a Los Angeles based Attorney and CPA practicing in the area of cross-border taxes. My firm handles cross-border US-Australian tax matters. Feel free to reach me at (213) 426 – 0186 or through this site if you need assistance with your US and/or Australian tax filings. We prepare tax filings for both countries.