An Instalment Activity Statement (IAS) is the form Australian businesses use to report and pay amounts that are not tied to GST: most commonly PAYG withholding from employee wages and PAYG income tax instalments. It exists for entities that report GST quarterly (or not at all) but still need to remit other amounts more frequently. That is the practical difference from a BAS: a BAS bundles GST together with PAYG and other obligations, while an IAS handles the non-GST amounts on their own, usually in the months between BAS periods.
Timely IAS lodgement matters because PAYG withholding is money already deducted from staff pay and held on the employer’s behalf. Miss the date and the firm exposes the client to general interest charges and ATO follow-up, neither of which inspires confidence. Without a repeatable process, IAS work tends to slip: a payroll run gets missed in the totals, an instalment amount is carried over from an old ATO notice, or the job stalls waiting on a client approval nobody chased. A documented workflow removes that guesswork.
When to run it
Most IAS obligations run monthly, typically due on the 21st of the following month for businesses reporting PAYG withholding on that cycle. Set the cadence to match each client’s reporting frequency and give the job a clear owner, usually the bookkeeper or accountant responsible for that client’s payroll. Build in enough lead time before the due date to chase approvals and resolve any variance queries.
How to run it in Tidyflow
Save this as a reusable job template so every IAS runs the same way regardless of who picks it up. Each step becomes a subtask your team checks off, keeping reconciliation, review, lodgement, and archiving in a fixed order. Put it on a recurring schedule with workflow management so a fresh job is created for each period without anyone remembering to set it up. The client-facing steps, approving the draft IAS and confirming payment, go out as items in the client portal, where clients respond and you can see at a glance who has actioned them. Lodged statements, payroll summaries, and approvals are then kept against the client for next period and any future ATO query.
Common pitfalls
- Treating the IAS like a BAS and accidentally including GST amounts that belong on the quarterly statement instead.
- Lodging before all pay runs for the period are finalised, so PAYG withholding totals do not match the payroll reports.
- Carrying forward a PAYG instalment amount from a superseded ATO notice rather than checking the current figure.
- Lodging without recording the client’s approval, leaving no audit trail if a figure is later disputed.
- Marking the job complete at lodgement and forgetting to confirm or schedule the payment, which is a separate obligation from lodging the form.