Many Australian businesses don’t realise that GST credits and fuel tax credits can permanently expire if they are not claimed within a strict four‑year time limit. This deadline is applied more tightly than other review periods, and once it passes the entitlement is lost, even if you have all the right paperwork and the expense was genuinely business‑related. The result can be thousands of dollars left on the table simply because the claim was made too late.
How the four‑year limit works
The clock generally starts from the due date of the original BAS in which you first could have claimed the credit. If the credit is not actually included in your assessment within that window, it expires. This is different from the BAS period of review many people are familiar with. A BAS may still be open for amendment, but that does not mean you can add older GST credits from that same period once the separate four‑year time limit has run out.
Why credits are being lost
Common admin moves do not pause the clock. A voluntary disclosure does not preserve your place in the queue. Sending a generic amendment request does not protect the entitlement either, because the credit must be processed and included in an assessment before the four years are up. If you discover an error close to the deadline and rely on slow workflows or extended reviews, the credit can still lapse. That is why acting early is critical.
Risk scenarios to watch
Businesses are most at risk when they uncover old invoices and try to claim years later, when they correct bookkeeping mistakes right on the cusp of the four‑year mark, or when they assume a pending review or amendment keeps everything alive. Groups that change GST apportionment methods late in the piece can also face extra scrutiny and timing pressure, which increases the chance of missing out.
Practical options to protect entitlements
If you identify unclaimed GST or fuel tax credits that are approaching the deadline, you have several practical routes. The fastest is often to include the amounts in your next BAS that is still within the four‑year window, with the understanding that the claim may be reviewed later. Where appropriate, lodging a revised BAS for the original period can be processed faster than a general amendment request. As a last resort, you can consider lodging a formal objection before the time limit expires, but this should be used sparingly because it requires a defensible position and adds complexity. If you are already in a compliance or assurance review, engage early and directly with the case team so there is enough time to preserve credits while the review runs its course.
Governance steps to prevent expiry
Build a simple cadence to keep credits current. Reconcile GST and fuel tax credits every month or quarter, not once a year. Run an aged invoices sweep each cycle to catch missed tax invoices. Tighten documentation and approval cut‑offs so invoices are captured in the correct period. For larger businesses, align tax, AP and procurement systems so GST coding and fuel usage data flow cleanly into BAS preparation. Where you rely on external advisers or shared service centres, agree service‑level timeframes that leave comfortable margin before the four‑year deadline. Finally, train your team on the difference between the BAS period of review and the separate entitlement time limit, so no one assumes an amendment automatically saves an old credit.
What to do now
If you suspect older credits are at risk, map the affected periods, calculate potential entitlements, and decide the fastest viable pathway to get them into an assessment before the deadline. Prioritise high‑value quarters and any fuel tax credits with complex eligibility or rate changes. Where process delays are likely, choose the option that gets an assessed outcome soonest rather than the one that is theoretically neatest on paper.
Bottom line
GST credits and fuel tax credits are valuable cash‑flow levers, but the window to claim them is shorter and stricter than many businesses expect. Early action, tight BAS governance and choosing the quickest compliant pathway can be the difference between a refund in your bank account and an entitlement that quietly disappears. If you want, I can turn this into a short client email, add an FAQ section for SEO, or supply a one‑sentence excerpt and meta description.
