Common Australian payroll mistakes and how to avoid them
Reviewed by Mellow Editorial Team, HR & payroll content team
Getting Australian payroll wrong is expensive — penalties, back-payments and damaged employee trust are all on the table. The mistakes below are the ones that come up most often, and most are preventable with the right processes.
Misclassifying workers as contractors
This is one of the most common and costly errors. If you pay someone as an independent contractor when they are, in substance, an employee, you are still liable for their superannuation, PAYG withholding, and potentially entitlements under the National Employment Standards.
The distinction turns on the whole working arrangement — not just what a contract says. Factors include whether the worker sets their own hours, uses their own tools, can subcontract, and bears commercial risk. The ATO and Fair Work Ombudsman both look past labels when auditing. If in doubt, get a determination from the ATO before you pay anyone as a contractor.
Incorrect PAYG withholding
Income tax in Australia is collected progressively through PAYG withholding at each pay event. The employer deducts the right amount based on each employee's tax file number declaration and any other withholding instructions — including whether the employee has a HECS/HELP debt.
HECS/HELP repayments work on a banded scale that sits on top of ordinary PAYG withholding. If an employee notifies you of a study debt and you fail to apply the correct withholding band, they end up with a tax bill they were not expecting. That erodes trust even though the shortfall is technically theirs to settle.
Common PAYG errors include:
- Using an incorrect tax scale (for example, applying the resident scale to a non-resident)
- Not updating withholding when an employee's circumstances change mid-year
- Forgetting to apply the Medicare levy surcharge for employees without appropriate private hospital cover where relevant
Run a withholding review whenever an employee submits a new TFN declaration or advises a change in circumstances.
Paying super late or on the wrong base
The Superannuation Guarantee rate is 12% of ordinary time earnings from 2026. Paying on total remuneration rather than ordinary time earnings — or vice versa — leads to systematic underpayment or overpayment.
Two traps to watch:
Timing. Super must be paid to a complying fund by the quarterly due dates. Paying it late triggers the Superannuation Guarantee Charge, which is calculated differently to the guarantee itself and includes interest and an administration levy. SGC is also not tax-deductible, unlike ordinary super contributions.
The ordinary time earnings base. Overtime does not form part of ordinary time earnings for SGC purposes, but most other regular payments do. If your payroll system is not correctly classifying pay types, the super base will be wrong from day one.
Check your award or enterprise agreement as well — some instruments require super contributions that exceed the statutory minimum.
Failing to meet Single Touch Payroll obligations
Every pay event must be reported to the ATO through Single Touch Payroll. STP replaced the old annual payment summaries and means the ATO has near-real-time visibility of your payroll. There is no grace period for late lodgements in the way there was with the old system.
End-of-year finalisation is due by 14 July. Finalisation confirms each employee's year-to-date figures so they can lodge their tax return. Missing this deadline delays returns for every employee on your payroll.
Practical steps:
- Confirm your payroll software is STP-compliant before you process any pays
- Reconcile your STP data to your general ledger at least quarterly, not just at year-end
- If you discover an error in a previous pay event, use a pay event amendment rather than trying to correct it in the next regular run
If you are managing payroll across multiple entities or countries, the reconciliation burden multiplies quickly. How Mellow runs payroll across six countries on one platform explains how centralised reporting can reduce that risk.
Underpaying leave entitlements
Under the National Employment Standards, full-time employees accrue four weeks of paid annual leave per year. Part-time employees accrue on a pro-rata basis. Shift workers covered by certain awards may be entitled to five weeks.
The entitlement is calculated on ordinary time earnings, not base rate alone — loadings and regular allowances can form part of the calculation depending on the award or contract. This is where underpayment most often creeps in: employers pay out leave at base rate and inadvertently exclude regular components that should be included.
Redundancy pay is also governed by the NES, on a scale that increases with years of service. Relying on memory or informal spreadsheets to calculate these figures is risky. Use award-specific payroll software or verify each calculation against the relevant instrument.
The broader principle across all of these errors is the same: payroll compliance depends on correct classification, accurate data, and timely reporting. Getting ahead of that — through regular reconciliations and system audits rather than reactive fixes — is what separates employers who stay off the ATO's radar from those who don't.
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