How ias works
A business below the GST registration threshold, or otherwise not registered for GST for any reason, does not lodge a BAS but may still need to report PAYG withholding on employee wages or its own PAYG income tax instalments each period. The ATO issues an IAS for these obligations on a monthly or quarterly cycle depending on the size, structure and reporting history of the business involved.
Because the IAS excludes GST labels entirely, it is generally simpler to complete than a full BAS but still depends heavily on accurate payroll records for PAYG withholding and correct instalment income figures being used. Only a TPB-registered BAS agent or the business itself may lodge an IAS, the same lodgment rule that applies equally to a full BAS statement.
Example
A small sole trader business is not GST-registered but employs two casual staff on a part-time basis. Each quarter it lodges an IAS reporting $1,600 in PAYG tax withheld from those employees' wages, with no GST labels to complete since the business falls under the GST turnover threshold entirely. Its BAS agent reviews the IAS workpapers before lodging the statement with the ATO on the due date each quarter.
IAS in QuickBooks Online vs Xero
QuickBooks Online's payroll and GST Centre can produce IAS-ready PAYG withholding figures even for businesses not registered for GST, without any extra manual setup required. Xero's Activity Statement report similarly adjusts to show only the PAYG withholding and instalment labels an IAS actually requires for that business.
Common mistakes
- A business that later registers for GST continues lodging an IAS instead of switching to a BAS, missing the GST labels it now needs to report.
- PAYG withholding figures on the IAS are taken from estimates rather than actual payroll records, producing a reported instalment amount that does not match reality.
- A business assumes lodging an IAS is optional below the GST threshold, when PAYG withholding and instalment obligations can still apply regardless of GST registration.
Why it matters
An IAS keeps PAYG withholding and income tax instalments current with the ATO even when a business is not yet GST-registered, so getting it wrong still carries real compliance risk. Only a TPB-registered BAS agent or the business itself may lodge it. Accurate IAS workpapers keep instalment obligations manageable instead of a surprise at tax time.
Related terms
How LedgerBPO handles ias
We track PAYG withholding and instalment figures through the period and prepare IAS workpapers ready for your TPB-registered BAS agent or accountant to review and lodge with the ATO. We do not lodge on your behalf under any circumstance at all.