How to Object to a GST/HST Assessment in Canada, and How It Differs

You have received a GST/HST notice of assessment and you think it is wrong. Maybe it is an input tax credit claim that was reduced, or a new housing rebate that was denied. The next step is a formal objection, and the timing rules are tight.

GST/HST objections look a lot like income tax objections, but several rules differ in ways that catch people out. This article walks through the main steps and flags where the two systems part ways. A lawyer or accountant can confirm how this applies to your situation.

This article covers Canadian federal tax law, which applies in every province.

The 90-day deadline is strict

Under Excise Tax Act s.301(1.1), a GST/HST objection must be filed within 90 days after the day the notice of assessment is sent. The 90 days count from the day the notice of assessment is sent, which the CRA calls the notice date.

This is where GST/HST differs from income tax. An individual objecting to an income tax assessment gets the later of one year after the return's filing-due date and 90 days after the notice. GST/HST has no one-year alternative; the deadline is 90 days from the notice date.

The objection must be on the prescribed form and set out the reasons and all relevant facts. The Minister may accept an objection that was not filed in the prescribed manner. Do not count on that, though. Aim to file properly and early.

How to file

• By mail or fax, using Form GST159, sent to the Chief of Appeals at the Appeals Intake Centre in Sudbury.
• Online through My Business Account by selecting "Register my formal dispute". Online objections go directly to the Appeals Division for validation and review.
• Through a representative, such as an accountant, who can use Represent a Client.

Whichever route you choose, keep proof of when you filed. If CRA sends a case number, use it in later correspondence.

Stricter rules for specified persons

Every GST/HST objection must set out the reasons and all relevant facts. GST/HST "specified persons" face a tougher standard. These are listed financial institutions and non-charities with threshold amounts over $6 million in both the current and previous fiscal year.

A specified person must describe each issue, state the relief sought and give the facts and reasons for each issue (ETA s.301(1.2)). If information is missing, there are 60 days to cure it (s.301(1.3)). If this may apply to you, get advice before filing.

Collection, interest and what happens next

For income tax, the Income Tax Act restricts collection of the disputed amount while an objection is pending. GST/HST is different: the CRA says it can keep collecting amounts you owe while the objection is pending.

Interest still applies, and you can pay all or part of the disputed amount to limit it. Whether to pay depends on your situation, so it is worth confirming with a lawyer or accountant.

Extensions and Tax Court appeals

If you miss the deadline, ETA s.303 allows an application to the Minister within one year after the objection deadline. You must show you were unable to act or had a bona fide intention to object, that an extension is just and equitable, and that you applied as soon as circumstances allowed. The application goes to the Chief of Appeals with a copy of the objection.

To appeal to the Tax Court, s.306 allows an appeal once the Minister has confirmed or reassessed, or 180 days after the objection was filed with no decision. Do not mix this up with income tax, where the wait is 90 days. After a confirmation or reassessment, the appeal cannot be instituted after 90 days from the day the Minister sends the s.301 notice.

Timing and next steps

For objections resolved in August 2026, GST/HST objections averaged 148 days for low complexity and 388 days for medium complexity, which includes new housing rebates and input tax credits. High complexity was over 500 days. These are monthly averages and change, so check the CRA's current figures.

• Find the notice date on your notice of assessment and count 90 days from it.
• Gather the notice, your records and any documents that support your position.
• Decide whether to file online, by mail or fax, or through a representative.
• Consider whether paying some or all of the disputed amount makes sense, given that interest keeps running and collection can continue.
• Diarize the 180-day and 90-day Tax Court dates.
• Speak with a lawyer or accountant early, especially if you are a specified person.

Revenu Québec generally administers GST/HST in Quebec, while the CRA administers it for selected listed financial institutions there. If your business is in Quebec, confirm which agency issued your notice.

Frequently asked questions