ATO objections

An ATO objection is the formal legal process for challenging an ATO assessment or decision you disagree with. You lodge it online, on the ATO objection form or in a signed letter, within the time limit, and it must state fully and in detail the grounds you rely on (Taxation Administration Act 1953 (TAA), s 14ZU).

As ATO objection lawyers, we act for businesses, company directors, families and individuals, as part of our work on ATO audits, reviews and objections. Our team includes lawyers and a Chartered Accountant, and we work alongside your accountant.

Which ATO decisions can you object to?

You can only object where a law gives you a right to object under Part IVC of the TAA (s 14ZL). The most common are:

• Income tax assessments and amended assessments (Income Tax Assessment Act 1936 (ITAA 1936), s 175A).
• GST and other indirect tax assessments, including assessments of a net amount (TAA Sch 1 ss 155-5, 155-90).
• Private rulings, generally unless there is already an assessment for the income year or period the ruling covers (Sch 1 s 359-60). See objecting to private rulings.
• Refusals to remit administrative penalties, where the penalty left is more than 2 penalty units (Sch 1 s 298-20(3)).
• Refusals to remit shortfall interest charge, where the amount not remitted is more than 20% of the additional tax (Sch 1 s 280-170).

Some decisions can't be objected to, such as a refusal to remit general interest charge under TAA s 8AAG (see what to do if interest remission is refused). For an amended assessment, you can generally only object to the matters that changed (s 14ZV).

If you don't object, you generally can't dispute the amount later, including when the ATO sues to recover the debt. Outside Part IVC proceedings, a notice of assessment is conclusive evidence that the amounts in it are correct (Sch 1 s 350-10, item 2).

Where do you lodge an ATO objection?

You can lodge through an ATO online services portal, on the ATO objection form or in a signed letter (ATO, Complete and lodge your objection, and Objection form for taxpayers, both last updated 4 June 2026):

• Individuals and sole traders: ATO online services (via myGov), or the PDF Objection form for taxpayers.
• Businesses, including sole traders: Online services for business (using myID), or the same PDF form.
• Tax agents: the Objection form for tax professionals.

There is no fee. You'll need to identify the decision (including the year or period) and give your reasons, supported by information and documents (ATO, What to include in your objection, 24 June 2024). For the portal steps, postal details and a letter outline, see how to write and lodge an ATO objection.

What makes a strong ATO objection?

• Grounds stated fully and in detail. Saying "the assessment is excessive" isn't enough. Identify each error, the law that applies and why your facts lead to a different result (s 14ZU(c)).
• Evidence. Records, contracts, bank statements and logbooks that prove the facts you rely on.
• Written for a hearing. In the Administrative Review Tribunal (ART) or the Federal Court, you are generally limited to the grounds in your objection unless the tribunal or court orders otherwise. You must also prove the assessment is excessive or otherwise incorrect, and what it should have been (ss 14ZZK, 14ZZO).

See how to write an ATO objection.

How long do you have to object?

The usual time limits in s 14ZW are:

Decision	Usual time limit
Income tax assessment: most individuals, and small and medium business entities (ITAA 1936 s 170(1) items 1–3A; for medium businesses, income years starting on or after 1 July 2021)	2 years after notice of the assessment
Income tax assessment: other taxpayers	4 years after notice of the assessment
Amended income tax assessment (objecting to the changes)	The later of the end of the original period (generally counted from the original notice) and 60 days after notice of the amended assessment (s 14ZW(1B), (1BA), (1C))
GST and other indirect tax assessment	Generally 4 years after notice of the assessment (s 14ZW(1)(bg), Sch 1 s 155-35)
Most other decisions	60 days after notice of the decision is served (s 14ZW(1)(c))

Time generally runs from the day notice of the assessment or decision is given or served, so check the date on the notice. For companies and super funds, the tax return is generally treated as the notice of assessment, given on the day it is lodged (ITAA 1936 s 166A(3)), and a GST return (usually your BAS) works the same way (TAA Sch 1 s 155-15). An objection to a shortfall penalty connected to an assessment generally has the same, longer time limit as the assessment (s 14ZW(1BB)).

Missed the deadline?

You can still lodge the objection with a written request asking the ATO to treat it as lodged in time, stating fully and in detail why it is late (s 14ZW(2)–(3)). The ATO weighs factors such as the length of the delay, your explanation and whether you have an arguable case (PS LA 2003/7, updated 2 April 2026, para 10). If it refuses, you can ask the ART to review the refusal (s 14ZX(4)). See objection time limits and late objections.

Who decides an ATO objection, and how long does it take?

The Commissioner must allow the objection, wholly or in part, or disallow it, and serve written notice of the decision (s 14ZY). A case officer may contact you or your adviser for further information, and the decision notice includes reasons (ATO, How we manage your objection, last updated 20 March 2026).

In practice, an objection against an earlier ATO decision is decided by an objection officer who had no involvement in the original decision-making (ATO practice statement PS LA 2023/2, para 3).

The law sets no fixed timeframe for a decision. But if you lodged in time and the ATO hasn't decided within 60 days (or, if within that time it asked in writing for information, 60 days after it receives it), you can give written notice requiring a decision. If there is still no decision 60 days after your notice, the objection is treated as disallowed (s 14ZYA). For a late objection the ATO has accepted, the first 60 days run from the day it agreed.

Once the objection is treated as disallowed, you can go to the ART or Federal Court. That isn't always the right move, so get advice first.

Do you have to pay while you object?

Generally, an objection doesn't change the due date, and general interest charge keeps accruing on anything unpaid. The ATO says it usually doesn't take recovery action on a disputed debt until the objection is finalised, but it expects large businesses to pay the disputed debt in full or at least 50% of it under a "50:50" arrangement (ATO, Steps to lodge an objection, last updated 14 October 2024). Its practice statement on disputed debts says the same: large business and wealthy group taxpayers must pay in full or enter a 50:50 arrangement, and for others, where the affairs are straightforward and the risk is low, it won't take recovery action while an objection, review or appeal is on foot (PS LA 2011/4, paras 6, 9–10).

Legally, though, a pending ART review or court appeal doesn't stop the ATO recovering the debt (ss 14ZZM, 14ZZR), and it can act where it assesses the risk as high. One exception: for a small business entity's assessment relating to its business, the ART can pause recovery during the review, if satisfied the review and the request aren't frivolous, vexatious, lacking in substance or otherwise intended to unduly impede the tax law's administration (ss 14ZZM(2), 14ZZH). See paying the tax during a review or appeal for how 50:50 arrangements work.

What happens after the ATO decides?

If the objection is allowed, the ATO usually amends the assessment and refunds anything it owes you. If it is disallowed in whole or part, 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, 14ZZN).

The ART can extend that time if it considers it reasonable (Administrative Review Tribunal Act 2024, s 19), but don't plan on it. An ART hearing is held in private if you ask (s 14ZZE). See challenging an objection decision in the ART or Federal Court.

How we help with an ATO objection

• Check the deadline. Whether the decision is objectable, and when time runs out.
• Draft the objection. Detailed grounds and evidence, written with a possible hearing in mind.
• Deal with the ATO. Information requests and, where sensible, settlement.
• Manage the debt. Payment, 50:50 arrangements and whether ATO penalties or interest can be remitted.
• Take it further. ART review or a Federal Court appeal, briefing experienced tax barristers.
• Work with your accountant. See how we work with accountants.

Next step

Send us the notice of assessment or decision you disagree with, any audit report or reasons the ATO gave, and the date you received the notice. If you've already lodged an objection, include a copy and any ATO letters since. In a short first call we'll confirm your deadline and whether an objection is the right step.