How to write an ATO objection

To write an ATO objection, identify the decision you disagree with, set out fully and in detail why it is wrong and what the right result is, include a declaration that the information is true and correct (signed, on paper), and lodge it within the time limit. You can lodge online, through your tax agent, on the ATO's paper form or in a signed letter.

The grounds matter most. If the ATO disallows the objection, you are generally limited to them in the Administrative Review Tribunal (ART) or the Federal Court. For the wider process, see our guide to ATO objections.

What does an ATO objection have to include?

An objection must be in the approved form, lodged within the period in section 14ZW, and state "fully and in detail" the grounds you rely on (Taxation Administration Act 1953 (TAA), s 14ZU).

1. The approved form. That is, the form the Commissioner has approved, with the required declaration and information, given in the manner the Commissioner requires (TAA Sch 1 s 388-50(1)). The ATO accepts its online form, its PDF forms, or a letter with the content it lists and a signed declaration (ATO, "Objection form – for taxpayers", last updated 4 June 2026).
2. Lodged in time. For an income tax assessment, generally 2 years after notice of the assessment is given to you for most individuals and small and medium businesses (for medium businesses, income years starting on or after 1 July 2021), and 4 years for other taxpayers (s 14ZW(1)(aa)). The clock starts when the notice is given, not when you spot the problem. For an amended assessment, it is generally the later of 2 years (or 4 years) after notice of the original assessment and 60 days after notice of the amendment (s 14ZW(1B), (1BA)). Many other decisions have 60 days from when notice is served on you (s 14ZW(1)(c)). See objection time limits and late objections.
3. Grounds stated fully and in detail. This doesn't mean long. The ATO should be able to see exactly which items you dispute, why, and what the right answer is.

Can you object to this decision?

You can only object where a law gives you the right (s 14ZL), and the notice usually says whether you can. Common examples:

• income tax assessments and amended assessments (Income Tax Assessment Act 1936 (ITAA 1936), s 175A)
• GST and other indirect tax assessments (TAA Sch 1 s 155-90), generally within 4 years after notice of the assessment (s 14ZW(1)(bg); Sch 1 s 155-35(2))
• assessments of shortfall and scheme penalties under Division 284 (Sch 1 s 298-30(2)). If the penalty relates to an assessment you have longer than 60 days to object to, you have that longer period (s 14ZW(1BB))
• a refusal to remit a penalty, where more than 2 penalty units remain payable (Sch 1 s 298-20(3))
• a refusal to remit shortfall interest charge on additional income tax (and certain other taxes), where the amount not remitted is more than 20% of the additional amount (Sch 1 s 280-170)
• private rulings, though generally not once there is an assessment for the year the ruling covers (Sch 1 s 359-60). See objecting to private rulings.

A refusal to remit general interest charge can't be objected to (TAA s 8AAG gives no objection right). See interest remission refused for the options there.

For an amended assessment, you can generally only object to the matters the amendment changed or matters relating to them (s 14ZV). If the audit included a position paper, your response to it is often the starting point for your grounds (see responding to a position paper).

How to write an objection letter to the ATO

There is no official ATO objection letter template, and the ATO doesn't prescribe a format. It says a letter must give full details of why the decision is wrong, contain a declaration that the information in it and any attached documents is true and correct, and be signed and dated (ATO, June 2026). This outline works for most objections, however you lodge.

1. Taxpayer details. Full name, TFN or ABN and contact details, plus your own details and authority if you are lodging for someone else.
2. The decision. Type of decision, date of the notice, year or period, any reference number and the amounts. For an amended assessment, the specific changes you dispute.
3. What you are asking for. For example, an amended assessment excluding a particular amount, or remission of a penalty in full.
4. The facts. A dated, chronological account, cross-referenced to the documents.
5. The grounds. Numbered, one point per ground, each saying what is wrong and why. Include alternatives, such as an argument against the penalty in case the tax argument fails.
6. The law. The provisions, ATO rulings and cases you rely on, and why the ATO's reading of them is wrong.
7. The correct figure. What the assessment or decision should have been. In the ART or Federal Court, you must prove the assessment is excessive or otherwise incorrect and what it should have been (ss 14ZZK(b), 14ZZO(b)), so show the calculation now.
8. Evidence. A numbered list of attached documents.
9. Extension request, if late. A separate written request (see below).
10. Declaration. Signed and dated, in the exact wording on the ATO's objection form page. Someone lodging for you needs the longer declaration on the same page.

What a well-written ground looks like

For example, suppose the ATO has disallowed $20,000 of subcontractor costs claimed by a company. (Illustrative only.)

• Too vague: "The company objects because the deductions are allowable and the assessment is excessive."
• Better: "Ground 1. The Commissioner was wrong to disallow $20,000 of subcontractor payments claimed for the 2024 income year. The payments were for installation work a named subcontractor did on client jobs. They were incurred in gaining the company's assessable income, so they are deductible under section 8-1 of the Income Tax Assessment Act 1997. Attachments 2 to 4 (invoices, bank statements and job sheets) show the work done and the amounts paid. The company's taxable income should be reduced by $20,000."

The second version gives the item, year, amount, legal basis, evidence and result sought. That is what "fully and in detail" asks for.

How do you lodge an objection with the ATO?

There is no fee to lodge an objection. The channels depend on who is lodging (ATO objection lodgement pages for taxpayers and tax professionals, last updated 4 June 2026).

Who is lodging	How
Individual or sole trader	Online services for individuals and sole traders (through myGov), the PDF Objection form for taxpayers (NAT 13471), or a letter
Business	Online services for business (using myID), the PDF form, or a letter
Tax agent	Online services for agents, the Objection form for tax professionals (NAT 13044), or a letter
Other authorised contact or representative	The paper form or a letter, with the signed declaration for someone lodging on another person's behalf

An authorised contact who isn't your tax agent, such as a relative or someone holding a power of attorney, can't lodge your objection online. They can lodge the paper form or a letter with a signed declaration, or prepare material for you to lodge online yourself (ATO, Complete and lodge your objection, last updated 4 June 2026).

Lodging on the ATO portal

In Online services for individuals and sole traders, or Online services for business, select Tax, Lodgments, Reports and forms, then Lodge an objection. Tax agents use the Practice level menu, then Reports and forms and Lodge an objection, and tick the declaration before submitting.

The ATO says the online form must be finished in one session, so draft your grounds separately and have attachments ready. Keep the receipt ID with a copy of what you lodged.

Lodging by post or fax

Post an objection letter to the Australian Taxation Office, PO Box 3524, Albury NSW 2640, or fax it to 1300 139 031 (ATO, "Objection form – for taxpayers", last updated 4 June 2026). Send the PDF form using the details on the form. If the deadline is close, allow for postal time and keep proof of when you sent it.

Common mistakes in ATO objections

1. Vague grounds. Saying only that the assessment is wrong or excessive risks not meeting s 14ZU, and leaves the ATO guessing.
2. Leaving out grounds. In the ART or Federal Court you are limited to the grounds in your objection unless the ART or court orders otherwise (ss 14ZZK(a), 14ZZO(a)). Permission isn't a formality: in RPPL Pty Ltd v Commissioner of Taxation [2025] FCA 1126, the court records that the ART allowed two of four proposed new grounds and refused leave under s 14ZZK for the other two (at [33]).
3. No figure and no evidence. Without them, you may not be able to discharge the burden of proof later (item 7 above).
4. No declaration or signature. The ATO says a letter needs a signed and dated declaration for the objection to be valid.
5. Assuming the debt is on hold. An objection doesn't change when the tax is due, and interest generally keeps running. A pending ART review or Federal Court appeal generally doesn't stop the ATO recovering the tax either (ss 14ZZM, 14ZZR), although for some small business assessments the ART can make an order affecting recovery while it reviews the decision (s 14ZZM(2)). Raise a payment arrangement for the disputed amount at the same time.

If you think of another ground after lodging, put it to the ATO in writing as soon as possible, before it decides. The ATO's view is that you can lodge more than one objection to an assessment, but only within the objection time limit and before it makes its objection decision (ATO ruling TR 2011/5, para 31). So if the objection period has ended, include a written request to treat the further objection as lodged in time (s 14ZW(2)).

What if you have missed the objection deadline?

You can still lodge it, together with a written request asking the ATO to deal with it as if it were lodged in time (s 14ZW(2)). The request must state fully and in detail the circumstances of, and reasons for, the late lodgement (s 14ZW(3)). The ATO won't consider a request without the objection itself (ATO practice statement PS LA 2003/7, para 7).

Under PS LA 2003/7 (last updated 2 April 2026), the ATO weighs the length of the delay, your explanation, whether you kept it informed that you disagreed, whether your case is arguable and whether the delay prejudices the ATO (para 10). Its examples of when an extension would generally be allowed, if nothing else points the other way, include illness, a decision sent to the wrong address, an adviser failing to act on prompt instructions, vulnerability, and an individual or small business with a 2-year limit lodging an arguable objection within 4 years (para 11). Changing adviser is not usually enough on its own (para 12).

If the ATO refuses, you can apply to the ART for review of the refusal (s 14ZX(4)).

What happens after you lodge an objection?

The ATO may ask for more information, then decides to allow the objection in whole or in part, or disallow it. It must serve written notice of the decision on you (s 14ZY).

How long does an ATO objection take?

The law sets no fixed time. If the ATO hasn't decided within 60 days after you lodged, or within 60 days after you give information it asked for by written notice within that time, you can give it written notice requiring a decision. For a late objection, the first 60 days run from when the ATO agrees to treat it as lodged in time. If there is still no decision 60 days after your notice, the objection is treated as disallowed (s 14ZYA).

If the objection is disallowed

You can generally apply to the ART for review or appeal to the Federal Court (s 14ZZ), within 60 days after you are served with notice of the decision (ss 14ZZC(1), 14ZZN). The ART can extend its 60-day period on application (Administrative Review Tribunal Act 2024, s 19), but that is discretionary, so don't plan on it. An ART application must be in writing and set out a statement of the reasons for the application (s 14ZZC(2)–(3)). See challenging an objection decision in the ART and Federal Court.

When is it worth getting help?

A simple objection, such as correcting an obvious processing error, is often something you or your accountant can lodge directly. Get advice first if the objection follows an audit, involves penalties or a large amount, or could end up in the ART, because the grounds you write now generally set the limits of that case.

We prepare objections as part of our work on ATO audits, reviews and objections, often alongside the client's accountant. See how we work with accountants.

Next step

Send us the notice of assessment or decision (every page), the date you received it, any position paper or audit findings, and a short note of why you think the ATO is wrong. If the deadline has passed, tell us why the objection is late. On a first call we'll confirm your deadline and tell you which grounds we think are worth taking.