GST Audit Under Section 65 and Section 66: When the Department Can Audit You and How to Prepare

So you've got a GST audit notice. First thing : don't panic, and definitely don't ignore it.

An audit under Section 65 or 66 of the CGST Act isn't the same as an income tax raid or a search operation. It's a document-based check, it comes with advance notice, and it follows a fixed timeline that the department itself has to stick to. What  matters is understanding why you were picked, what the officer will look at, and whether your paperwork can hold up.

This piece walks through both sections in plain language, Section 65 (the routine departmental audit) and Section 66 (the special audit ordered mid-investigation), plus what usually triggers one and how businesses in India  prepare for it.

Quick things to know before we get into detail:

1.) Section 65 is run by GST officers themselves; Section 66 is outsourced to an independent CA or Cost Accountant

2.) You get at least 15 working days' notice before a Section 65 audit starts

3.) A Section 65 audit has to wrap up in 3 months, though the Commissioner can push it out by another 6

4.) A special audit under Section 66 runs on a 90-day clock, extendable by 90 more days

5.) Neither audit means you owe money automatically that only happens if a formal notice under Section 73 or 74 follows

What Is a GST Audit?

Under the law, an audit is just an examination of your returns, invoices, and books to check if what you've declared : turnover, tax paid, ITC claimed, refunds taken - matches reality.

One thing people get confused about: the old rule requiring every business above ₹2 crore turnover to get a CA/CMA audit done was scrapped back in 2021. What's left now is entirely at the department's discretion. They pick who gets audited, and it's usually not random.

Section 65 vs Section 66 : Side-by-Side Difference Table
 

Why Do Businesses Get Picked for a GST Audit?

There's no lottery system here. GSTN's data analytics does most of the heavy lifting, flagging accounts that look "off" compared to their own filing history or their industry peers. The patterns that tend to draw attention:

Mismatches between GSTR-1, GSTR-3B, and GSTR-2B are probably the single biggest reason. If your outward supply figures in GSTR-1 don't line up with what you've reported in 3B, or your ITC claims don't reconcile with 2B, that's an easy flag for the system to catch.

Beyond that, a tax-to-turnover ratio that's lower than what's typical for your sector, unusually high ITC claims relative to output tax, large cash refund claims (common in export businesses or where there's an inverted duty structure), too many credit/debit notes without a clear paper trail, or goods and services classified under a tax slab that looks off compared to similar businesses.

None of this means you did anything wrong. It just means your numbers looked worth a closer look.

What Records Will They Ask to See?
 

How the Section 65 Process Plays Out

It starts with a notice, FORM GST ADT-01, sent at least 15 working days before the audit date. The officer can choose to visit your premises or ask you to bring records to the GST office; either is allowed.

The audit itself covers a financial year or a multiple of it, and the officer goes through turnover figures, ITC claims, tax classification, and refund utilisation, cross-checking everything against your books.

Once it's done, you're not left guessing within 30 days, the officer has to share findings in FORM GST ADT-02. At that point you have two real options: pay up voluntarily if the observation is genuine, or push back if you think it's wrong. If it's not resolved amicably, it escalates into a formal show-cause notice under Section 73 (no fraud involved) or Section 74/74A (where fraud or suppression is alleged).

Worth repeating: an audit finding by itself isn't a tax demand. The department still has to go through the formal notice process before recovering anything.

Preparing for a Department Audit: What Helps

Reconcile your returns monthly instead of scrambling at year-end. GSTR-1 vs 3B vs 2B mismatches are avoidable if someone's checking them every month rather than once a year.

Keep a clean paper trail for every ITC claim : invoice, e-way bill, delivery proof, payment record. If an officer asks "prove this credit is genuine," you want the answer ready in five minutes, not five days.

Consider a pre-audit , get your GST consultant or a CA to run through your books before the department does. It's far cheaper to fix an error yourself than to have it discovered during an official audit.

If you do find a genuine short payment somewhere, pay it voluntarily before the audit. It cuts down interest exposure and, more importantly, changes how the whole audit is perceived.

Don't try to handle the audit team alone if you're not confident with the technicalities; an authorised representative (your CA or tax consultant) can represent you and often smooths out a lot of friction.

And don't sit on the ADT-01 notice. Ignoring it can lead the officer to go with a best-judgment assessment under Section 63, which almost never works in the taxpayer's favour.

What If You Just Don't Cooperate?

Not a good idea. Obstructing the audit or refusing to hand over records invites a penalty under Section 125 - up to ₹25,000. And if the officer genuinely can't proceed because of your non-cooperation, they're allowed to fall back on best-judgment assessment under Section 63, which typically means higher liability than what an honest audit would have found anyway.

FAQs That People Ask About GST Audits

Q1. What's the real difference between Section 65 and Section 66 audits? 

Section 65 is the department's own routine audit, based on risk flags in your filing data. Section 66 is a special audit ordered when an officer suspects something specific (like undervaluation or excess ITC) and wants an independent CA or CMA to dig deeper.

Q1. How much notice do I get before a GST audit? 

Minimum 15 working days, delivered through FORM GST ADT-01.

Q2. How long can a Section 65 audit drag on? 

Three months from when it starts, and the Commissioner can extend that by up to 6 more months if there's a documented reason. Nine months, worst case.

Q3. Can I just refuse to give the officer my records? 

No, cooperation is mandatory under Section 65(3). Refusing invites penalties and possibly a best-judgment assessment, which is worse for you either way.

Q4. Who pays for a special audit under Section 66? 

The government does. The Commissioner decides and pays the nominated CA/CMA's fee, it costs the taxpayer nothing directly.

Q5. If my accounts are already audited elsewhere, can GST still order a special audit? 

Yes. Section 66(3) makes it clear, a special audit can happen even if you've already been audited under the Companies Act, Income Tax Act, or another GST provision.

Q6. What happens once the audit report comes in? 

You either settle the amount voluntarily, or the department issues a show-cause notice under Section 73 or 74/74A and things move into formal proceedings from there.

Q7. Does getting audited always mean I'll owe extra tax? 

Not at all. Plenty of audits close out with minor clarifications, or nothing at all, once the reconciliation is sorted.

Bottom Line

A GST audit isn't something to dread if your books are in order. Most of the pain people go through comes from disorganised records, not from the audit itself. Reconcile monthly, keep your ITC documentation tight, and respond to notices the day they arrive that alone puts you ahead of most businesses that get selected.

If you've got an audit notice sitting in your inbox right now, or just want someone to run a reconciliation check before the department does, get in touch with GST Filling - we help businesses prepare for exactly this.

Author Bio

Harshita Saini is an SEO Executive at LegalDev, where she leads SEO and content strategy for gstfilling.co. She researches the latest GST notifications, tax reforms, and compliance updates to create accurate, search-driven content for businesses across India.
Her expertise lies in simplifying complex GST laws into easy-to-understand guides, helping entrepreneurs, startups, and taxpayers stay compliant, avoid penalties, and make informed tax decisions with confidence.