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NZ vs AU GST returns — forms, labels, and how Xero generates them

· 9 min read
Shan Xiao
Developer & Bookkeeping Learner

New Zealand and Australia both operate a GST system, but the practical experience of preparing and filing returns differs a lot once you get into the return form structure (NZ) vs BAS / Activity Statement labels (AU), and how accounting software (like Xero) maps transactions into those structures.

This post focuses on:

  1. Common GST principles (what’s the same in both countries)
  2. Differences in return forms + links to official documents
  3. Operational details in Xero: what Xero includes, where the rules come from, and what you can configure

1) Common tax systems and basic principles​

At a high level, NZ GST and AU GST share the same “value-added / consumption tax” mechanics:

  • GST is charged on taxable supplies (sales) and reported as GST payable (often called “output GST”).
  • GST on business purchases can be claimed when eligible (often called “input GST” or a GST credit).
  • Net GST payable/refundable for a period is the difference between GST collected and GST claimed.
  • Record quality matters: tax invoices (AU) / tax invoices and evidence (NZ) determine whether GST can be claimed.
  • Timing depends on your reporting basis (cash/payments vs accrual/invoice). That choice drives whether transactions appear based on payment date vs invoice/transaction date.

Where people get caught out is that “same principles” doesn’t mean “same reporting artefacts”: the return forms and label/box schemas are different, and software support differs.

NZ: GST101A + IR375 (IRD)​

In NZ, Inland Revenue’s documentation uses named forms and guides:

  • IR375 (GST guide) — a comprehensive guide describing GST concepts, filing, adjustments, and supply types.
  • GST101A (Goods and services tax return) — the return used to calculate and file GST.

Official IRD links:

What this means in practice:

  • NZ return discussions tend to be framed around the GST return itself (and the guide that explains it).
  • Adjustments and edge cases are described in “guide language” (IR375), and you’re expected to apply it to the GST101A return.

AU: BAS / Activity Statement labels (ATO)​

In Australia, GST is commonly reported via the Business Activity Statement (BAS) (and related activity statements). The BAS uses a label scheme.

The ATO BAS hub explicitly lists the GST-related labels such as G1, G2, G3, G10, G11, G21, G22, G23, G24, 1A and 1B:

The ATO also explains that businesses report and pay GST and claim GST credits by lodging a BAS or an annual GST return:

What this means in practice:

  • AU reporting is often discussed in terms of BAS labels (e.g., “what goes to 1A/1B?”).
  • You may be reporting multiple obligations on the BAS beyond GST (PAYG withholding, PAYG instalments, etc.), depending on your circumstances.

3) Operational details in Xero (NZ vs AU)​

This section is less about “how GST works legally” and more about what Xero actually does and which settings influence the output.

3.1 The single biggest shared concept in Xero: the GST system account​

Both NZ and AU behaviours rely on the same Xero principle:

  • Xero uses one system account for GST and includes amounts from that account when producing the relevant return/report.

NZ (GST return) — Xero Central:

AU (Activity Statement) — Xero Central:

Implication: if you’re trying to “model” a return outside Xero, you typically start by understanding what posts into that GST system account.

3.2 How Xero decides which transactions appear (cash vs accrual)​

NZ (payments basis vs invoice basis):

  • Payments basis: includes transactions paid during the return period (and includes journals only if “Show journal on cash basis reports” is selected).
  • Invoice basis: includes approved transactions dated during the return period, including unpaid.
  • Spend/receive money transactions are included on transaction date for both bases.

Source:

AU (cash vs accrual for Activity Statement):

  • Cash: inclusion based on payment date.
  • Accrual: inclusion based on transaction date.
  • Manual journals are included based on journal date, and only appear on cash basis reports if the “Show journal on cash basis reports” option is selected.

Source:

3.3 What you can configure (and what you can’t)​

Xero is opinionated. A useful way to think about it:

  • You can configure classification and timing (tax rates, defaults, basis settings, lock dates).
  • You generally cannot directly edit “GST amounts” inside a return; corrections are done via transaction fixes or adjustments.

Configuration items that commonly affect the output​

NZ-focused settings (GST Return)

  • GST basis (payments vs invoice) and GST registration settings — in financial settings.
  • Tax rates (default rates and any custom rates) that determine what posts into the GST system account.
  • Transaction tax treatment (tax inclusive/exclusive/no tax) and per-line tax rates.
  • Late claims handling (for finalised GST returns).

Key Xero sources:

AU-focused settings (Activity Statement / BAS)

  • Activity statement settings (GST details) — configured in financial settings.
  • Tax treatment defaults and per-transaction selection of inclusive/exclusive/no tax.
  • Tax rates (including whether you’re using basic vs advanced tax rates for BAS reporting).
  • Lock dates after finalising.

Key Xero sources:

Limits and design constraints worth knowing​

Practical workflow: how to “prove” where numbers come from​

If you’re implementing bookkeeping logic or reconciling Xero to the official forms, here’s a repeatable workflow:

  1. Start from the authority’s structure
    • NZ: confirm you’re targeting GST101A and the concepts described in IR375.
    • AU: confirm whether you’re targeting the BAS / Activity Statement and which labels apply.
  2. Start from Xero’s “what gets included” rules
    • Confirm the basis setting (payments/cash vs invoice/accrual).
    • Confirm that GST is posting to the system GST account.
  3. Validate classification
    • Review tax rates (default + custom) and confirm they map to the intended reporting treatment.
    • Review tax treatment defaults and overrides (contacts, per-line tax rates).
  4. Reconcile before filing
    • NZ: use the GST Reconciliation report.
    • AU: use the Activity Statement report and transaction drill-down.
  5. Lock the period after finalising
    • Helps prevent late changes that produce late claims (NZ) or unexpected BAS differences (AU).

References​

Inland Revenue (NZ)​

Australian Taxation Office (AU)​

Xero Central​