Tax Losses of Earlier Income Years
Losses brought forward should be reflected here. Those losses are then available to offset any taxable income.
Finally, any balance of losses either brought forward or generated in the current year will be carried forward to the following tax year.
Note - This applies to all losses, not just business losses.
Find the losses section at the bottom of the "Deduction" Tab.
ATO Related Article :
How to use Deferred Business Losses (Carried forward Loss)