Insight
Dec 3, 2025
Mackisen
Do I Need a Tax Lawyer, or Can My Accountant Handle a GST Audit?
When Revenu Québec launches a GST/QST audit, many businesses owners panic and wonder whether they need to hire a tax lawyer, rely on their CPA, or use a combination of both. The truth is that most GST/QST audits begin as routine verification exercises but they can escalate quickly if the auditor suspects non-compliance, negligence, or intentional misreporting. Knowing who should represent you at each stage can protect your rights, reduce assessments, and prevent penalties.
This guide explains when your accountant is enough, when a tax lawyer becomes essential, and how both professionals work together during a sales tax audit.
When a CPA Is Enough for a GST/QST Audit
Most audits can be handled entirely by your accountant, especially when the issue is financial, not legal.
Your accountant is the right professional if the audit involves:
• missing invoices or receipts
• input tax credit/refund validation
• sales vs. deposits reconciliation
• POS or e-commerce discrepancies
• bookkeeping errors
• reasonable business explanations
• refiling or correcting returns
• reorganizing documentation
In these cases, the CPA communicates with Revenu Québec, provides documentation, explains accounting details, and resolves questions efficiently.
Why a CPA Works for Most Audits
• CPAs understand GST/QST rules deeply
• They know how Revenu Québec auditors operate
• They handle documentation cleanup
• They prepare reconciliations and corrections
• They have experience responding to verification demands
For 80–90% of audits, a CPA is fully sufficient.
When You Need a Tax Lawyer (Critical Situations)
A tax lawyer becomes essential when the audit shifts from financial to legal risk.
You need a tax lawyer if:
• the auditor threatens gross negligence penalties
• the auditor questions your intent
• the auditor implies fraud or misrepresentation
• the audit involves offshore income or cross-border structures
• criminal investigations are mentioned
• you are asked to provide sworn statements
• there are accusations of “false invoices”
• the auditor misinterprets the law and refuses corrective evidence
• the auditor becomes adversarial or hostile
• Revenu Québec is preparing an official reassessment
These scenarios move beyond accounting they require legal protection.
What a Tax Lawyer Does
• protects your rights during the audit
• stops inappropriate auditor behaviour
• challenges incorrect legal interpretations
• drafts legal argumentation
• negotiates penalty reductions
• manages objections and appeals
• represents you before courts if needed
When You Need Both a CPA and a Tax Lawyer
The strongest defense in a complex GST/QST audit is often a CPA + tax lawyer team.
This combination is ideal when:
• the numbers are messy AND the law is unclear
• reconstructing records requires accounting expertise
• legal arguments are needed to dispute auditor positions
• penalties need to be argued legally
• objections to assessments must be filed
• the audit scope expands beyond GST/QST (income tax, payroll, etc.)
The CPA handles facts and documents.
The lawyer handles legal interpretation and rights.
Together, they create a full defense strategy.
How GST/QST Audits Usually Escalate
Understanding the progression helps you know when to bring in a lawyer.
Verification letter → a CPA is enough
Information request → CPA prepares documents
Auditor disputes transactions → CPA explains
Auditor threatens penalties → lawyer may be required
Notice of Reassessment draft → CPA + lawyer
Formal Notice of Assessment → lawyer required
Objection/appeal → lawyer leads, CPA supports
Most audits never reach stages 5–7 when handled properly from the start.
The Risk of Representing Yourself
Responding directly to an auditor without professional support is one of the biggest mistakes business owners make.
Risks include:
• saying something that harms you
• providing unnecessary documents
• confusing taxable vs. exempt supplies
• triggering more audit periods
• accepting adjustments you don’t understand
• exposing unrelated years to review
Auditors are trained taxpayers are not.
Mackisen Strategy
Mackisen CPA works as your first line of defense in GST/QST audits. We:
• handle communication
• reconcile sales, deposits, ITCs, and ITRs
• collect and prepare all documentation
• fix bookkeeping errors
• correct tax coding
• negotiate with auditors
• prevent escalation
• recommend a tax lawyer when risks become legal
Our approach resolves most audits before a lawyer is ever needed.
Real Client Experience
A retail business had missing receipts and POS mismatches. Mackisen reconstructed records, communicated with the auditor, and closed the audit with no adjustments.
A consultant faced potential negligence penalties. Mackisen brought in a tax lawyer at the right time, and all penalties were removed.
A software startup received a proposed reassessment of $38,000. CPA + lawyer collaboration reversed 90% of the adjustments.
Common Questions
Do I always need a tax lawyer for an audit?
No only when legal risk arises.
Will a CPA handle auditor communication?
Yes CPAs commonly manage all communication.
Can penalties be removed?
Often yes, with strong accounting and legal arguments.
Can a tax lawyer fight a reassessment?
Yes objections and appeals are legal procedures.
Why Mackisen
With more than 35 years of combined CPA experience, Mackisen CPA Montreal protects businesses during GST/QST audits, works with top tax lawyers when needed, and ensures your financial and legal interests are fully defended.
