You need report to Australia ATO every year once start. Just like HK, you will receive Green Letter from Tax Dept every year. Legally speaking, yes you need pay 兩邊既稅. ATO has no right to check your income in HK Tax dept.
https://www.ato.gov.au/Individuals/International-tax-for-individuals/Work-out-your-tax-residency/
[p=24, null, left]If you're an Australian resident for tax purposes:
You generally have to declare all income you earned both in Australia and internationally on your tax return.
Yes, you need File tax return every year by Law, this is your duty once you have TFN. (Just like HK, HK govt give you green letter/etax, you don't reply does not mean ok.)
Once you apply TFN, you cannot delete until you revoke your PR.
My friend wife is citizen, so the husband revoke since he can get back when old for sure