The ATO regularly reviews, and sometimes cancels, inactive Australian Business Numbers (‘ABNs’). The ATO may review a taxpayer’s ABN if the taxpayer has not reported business activity in their tax return, or there are no signs of business activity in other lodgments or third-party information.
If the ATO thinks a taxpayer is no longer using their ABN, it will contact them by email, letter or SMS.
If the taxpayer is still running a business, the ATO will tell them what they need to do to keep their ABN. If they are no longer in business, they do not need to do anything -— the ATO will cancel their ABN.
Taxpayers who think they are still entitled to an ABN that has been cancelled need to reapply for it. If they restart their business activities, they should be able to reapply for the same ABN, provided that their business structure is not changing.