BAS & IAS Services

Staying on top of BAS and IAS lodgements is one of those compliance tasks that can quietly spiral if it is not managed properly. Miss a deadline, code a transaction incorrectly, or carry forward a bookkeeping error, and the ATO will notice.



At Taxcor, we handle BAS and IAS preparation and lodgement for businesses of all sizes — from sole traders lodging quarterly GST through to larger companies managing monthly payroll, PAYG withholding, and complex GST reconciliations. Our registered tax agents take care of the detail so you can get on with running your business.

Accurate reporting

Professionally managed

Improve cash flow

Avoid common errors

What Is a Business Activity Statement (BAS)?

A BAS is a form lodged with the Australian Taxation Office to report and pay various business tax obligations. Businesses registered for GST are generally required to lodge BAS monthly, quarterly, or annually depending on their turnover and ATO reporting cycle.



A BAS may include:

  • Goods and Services Tax (GST) collected and credits claimed
  • PAYG withholding tax on employee wages
  • PAYG instalments on business income
  • Luxury Car Tax (if applicable)
  • Fringe Benefits Tax instalments (if applicable)
  • Other ATO reporting obligations

Example:

ABC Plumbing Pty Ltd is registered for GST and employs two staff. Each quarter, the business reports GST collected on sales, GST paid on business purchases, and PAYG withholding deducted from employee wages through its BAS.

What Is an Instalment Activity Statement (IAS)?

An IAS is used by businesses or individuals that have PAYG withholding or instalment obligations but are not required to report GST on a BAS. Common situations where an IAS applies include businesses not registered for GST, employers reporting PAYG withholding monthly, and individuals paying PAYG instalments on investment or other income.


Example: Sarah is a sole trader consultant whose annual turnover is below the GST registration threshold. She employs one casual assistant and must report PAYG withholding to the ATO through monthly IAS lodgements.

Why Accurate Reporting Matters

Incorrect or late BAS and IAS lodgements can result in ATO penalties and interest charges, inaccurate GST reporting, payroll compliance issues, cash flow problems, and an increased risk of ATO review or audit. Beyond compliance, accurate and regular reporting gives you real insight into the financial health of your business throughout the year.

Things to Consider

GST and payroll reporting can become significantly more complex as a business grows. Businesses may need to manage GST coding across multiple expense categories, reconcile payroll, handle contractor PAYG obligations, and integrate data across several software platforms.


The most common reason businesses run into BAS problems is disorganised bookkeeping — incomplete records, unreconciled bank accounts, or personal and business expenses mixed together. Keeping clean, up-to-date books throughout the year makes BAS preparation straightforward and reduces the risk of errors.



Businesses must also retain supporting records including tax invoices, receipts, bank statements, payroll records, superannuation records, contractor payment records, and asset purchase documentation. The ATO generally requires these to be kept for at least five years.

How We Can Help

We provide BAS and IAS services for businesses across a wide range of industries, including construction, trades, medical and dental, hospitality, retail, transport, professional services, and eCommerce. Our services include:

BAS preparation and lodgement

IAS preparation and lodgement

GST registration and advice

PAYG withholding and instalment reporting

Bookkeeping and bank reconciliations

Payroll processing and superannuation reporting

Cash flow reporting

ATO liaison and correspondence

Overdue BAS and IAS lodgements

GST reviews and corrections

Xero, MYOB, and QuickBooks support

Management reporting

Fixed-Fee Packages

  • Fixed annual or monthly pricing — no hidden costs
  • Monthly bookkeeping and quarterly BAS packages available
  • General accounting advice included
  • ATO compliance assistance
  • Basic tax planning included

Cloud Accounting Software

We support Xero, MYOB, and QuickBooks, and can assist with software setup, GST coding reviews, bank feed setup, payroll configuration, and ongoing training and support.

Frequently Asked Questions

  • Do I need to lodge a BAS?

    If your business is registered for GST, yes. The ATO requires BAS to be lodged monthly, quarterly, or annually depending on your reporting cycle and turnover.

  • What is the difference between a BAS and an IAS?

    A BAS covers GST, PAYG withholding, and other ATO obligations in one form. An IAS is used where GST is not applicable but PAYG withholding or PAYG instalments still need to be reported.

  • What happens if BAS is lodged late?

    Late BAS lodgements attract failure-to-lodge penalties from the ATO, which increase the longer the lodgement remains outstanding. Interest charges may also apply on any amounts owing. Lodging on time — even if you cannot pay immediately — avoids the worst of these penalties.

  • Can you help with overdue BAS lodgements?

    Yes. We regularly assist businesses that have fallen behind on BAS lodgements — sometimes by months, sometimes by years. We organise the records, reconcile accounts, prepare the outstanding statements, and lodge them with the ATO. In many cases, we can also negotiate penalty remission where appropriate.

  • Can I lodge BAS myself?

    Yes. However, many business owners find that using a registered tax or BAS agent reduces errors, saves time, and gives them confidence that their reporting is accurate and compliant.

  • Do I need to register for GST?

    Businesses must register for GST once annual turnover reaches $75,000. For ride-sourcing and taxi drivers, GST registration is compulsory from the first day of operation, regardless of income.

  • Can you correct BAS mistakes?

    Yes. We frequently review BAS statements that were prepared and lodged by business owners themselves and find errors in GST coding, missed credits, or payroll reporting issues. We can prepare amendments and corrections where needed.

  • Can bookkeeping software help with BAS?

    Absolutely. Xero, MYOB, and QuickBooks automate much of the transaction coding, bank reconciliation, and GST tracking that feeds into BAS preparation. When set up correctly, they significantly reduce the time and risk involved in BAS reporting.

  • Can you help with payroll and PAYG withholding?

    Yes. We assist businesses with payroll processing, PAYG withholding calculations, Single Touch Payroll (STP) reporting, and superannuation obligations.