IITR.301105 states that the occupation code and occupation description must be present in the return where a Salary or wages payment summary or a Foreign employment income payment summary is present or where there is a claim for work-related expense deduction.
If you have Salary or wages present at Item 1 in your Individual tax return, then you must complete the Occupation code and description.
If you have completed a Foreign Employment PAYG summary, then you must complete the Occupation code and description at Item 1 in the Main form.
If you have completed a Work-related Expenses Schedule or any items in the Main form at Deductions D1 to D5, then you must complete the Occupation code and description at Item 1 in the Main form.
If you have Allowances, earnings, tips, and directors' fees completed at Item 2 in the Main form, then you must complete the Occupation code and description at Item 1 in the Main form.
Note: The occupation code chosen may have been removed by the ATO for use, review the article Occupation Code Errors for recent changes to the occupation codes no longer accepted by the ATO.