Some lenders will only approve a loan if a Notice of Assessment (NOA) is provided.
A Notice of Assessment is an official document prepared by the Australian Taxation Office (ATO) which is a statement of the tax that you have paid in the last financial year and the tax that you owe the government or the tax refund that they owe you. It is mailed to you around two weeks after you lodge your tax returns.
Since it shows your taxable income for the last financial year and is also an official document from the government, lenders have definite proof of your income and will consider your mortgage application.
The problem that many people have is that their income has changed since the last financial year so they cannot use this method to prove their current income. If the borrower did not work for the same employer, the bank may decline their loan due to not meeting their income verification requirements.