1. GST Audit: Why It Exists and Who Is at Risk

GST audit is the department’s primary mechanism to verify that a registered person has correctly declared their tax liability, availed only eligible Input Tax Credit (ITC), and filed returns accurately. It is separate from the self-certified audit under Section 35(5) — which was struck down by the Supreme Court in Union of India vs Bharati Airtel Ltd (2021) — and far more consequential for your clients.

The CGST Act, 2017 provides two types of audits that a CA must know cold:

• Section 65 — Audit by a GST Commissioner or any authorised officer (Departmental Audit)
• Section 66 — Special Audit directed by an Assistant Commissioner or above, conducted by a nominated CA or Cost Accountant

2. Section 65 — Departmental Audit: Everything Explained

Section 65 of the CGST Act empowers the Commissioner of GST or any officer authorised by him to audit the accounts and records of any registered person. This is the standard, most frequently encountered form of GST audit. It can be initiated at the business premises or at the tax office.

Who Can Authorise a Section 65 Audit?

The audit is initiated by the Commissioner (Central or State, depending on jurisdiction). The authorised officer must be at the rank of Superintendent or above. The registered person receives a notice at least 15 working days in advance specifying the date, time, and place of the audit — as required under Rule 101(2) of the CGST Rules, 2017.

Scope of the Audit

The officer can examine books of accounts, tax invoices, debit/credit notes, e-way bills, bank statements, stock registers, and any other documents relevant to GST compliance. They will specifically look at:

• Correctness of turnover declared in GSTR-1 and GSTR-3B
• Eligible vs claimed ITC — cross-verification with GSTR-2B
• Classification of goods/services and applicable tax rate
• Exempt supplies and reversal obligations under Rule 42/43
• Compliance with e-invoicing and e-way bill provisions
• Payment of tax on advance receipts and RCM transactions

Time Limits Under Section 65

As per Section 65(4), the audit must be completed within 3 months from the date of commencement. The Commissioner can extend this by a further period not exceeding 6 months — so the maximum audit duration is 9 months. “Commencement” means the date on which records or documents are made available by the taxpayer.

Obligations of the Taxpayer

Under Section 65(3), the registered person must:

• Facilitate the audit and make available all required records
• Provide a suitable place for audit if conducted at business premises
• Give true and correct information to the officer
• Render assistance as required — including to any system for electronic access

Obstruction or refusal attracts penalty under Section 125 of the CGST Act (general penalty up to ₹25,000). More critically, if the officer cannot conduct the audit due to non-cooperation, they can proceed with best judgment assessment under Section 63.

3. Section 66 — Special Audit: When and Why It’s Triggered

Section 66 is a different beast. Unlike Section 65 — which is routine and conducted by departmental officers — a special audit under Section 66 is ordered when the value of supply, ITC claimed, or the complexity of transactions is such that the officer believes an expert is needed.

Who Orders It?

An officer not below the rank of Assistant Commissioner, with prior approval of the Commissioner, can direct the registered person to get their accounts examined and audited by a nominated Chartered Accountant or Cost Accountant. The CA or CMA is chosen by the Commissioner — not by the taxpayer.

Grounds for Triggering Section 66

The law specifies that a special audit can be ordered “at any stage of scrutiny, inquiry, investigation or any other proceedings” when the officer forms an opinion that:

• The value has not been correctly declared, or
• The credit availed is not within normal limits

This makes Section 66 particularly dangerous in cases involving complex valuation disputes, large-scale ITC fraud allegations, or multi-entity transaction structures the departmental officer finds difficult to unravel independently.

Time Limit and Extension

The nominated CA or CMA must submit their report within 90 days of the direction. The Commissioner can extend this by a further 90 days — so the maximum is 180 days. The audit cost is borne by the department, not the taxpayer.

4. Section 65 vs Section 66: Key Differences at a Glance

5. Documents Your Client Must Produce

One of the most important things a CA can do before a GST audit is help the client organise their documentation. The following is what auditors will typically demand — having it ready reduces audit time and demonstrates compliance culture.

• Filed GSTR-1, GSTR-3B, GSTR-2B for the audit period
• Purchase register and sales register (matching with returns)
• All GST-compliant tax invoices issued and received
• Input Tax Credit register with GSTR-2B reconciliation
• ITC reversal workings under Rule 42 and Rule 43 (if applicable)
• E-invoices and IRN numbers (if e-invoicing applicable)
• E-way bill log for all outward/inward movements above threshold
• Bank statements for the audit period
• Audited financial statements and trial balance
• Stock register (opening, receipts, issues, closing — with reconciliation to invoices)
• Contracts, agreements — especially for services, job work, or import/export
• RCM payment records — Section 9(3) and 9(4) supplies
• GSTR-9 and GSTR-9C (annual return and reconciliation statement)
• Debit/credit note register with reason codes
• Any assessment orders, prior audit reports, or SCNs received

6. Step-by-Step: How a GST Audit Under Section 65 Unfolds

1. Audit Authorisation: Commissioner issues authorisation in FORM GST ADT-01. The authorised officer is designated.
2. Notice to Taxpayer: Advance notice given at least 15 working days before commencement (Rule 101(2), CGST Rules). Notice specifies date, time, and place of audit.
3. Commencement of Audit: Officer arrives at business premises or tax office. The taxpayer must provide all required records within the stipulated time.
4. Examination of Records: Officer verifies returns, invoices, ITC claims, payments, and reconciliations. They may request further documents or explanations.
5. Audit Findings Discussed: Before finalising findings, the officer gives the taxpayer an opportunity to explain discrepancies — this is a statutory right under Section 65(6).
6. Audit Report Issued: Within 30 days of completion, the officer communicates findings in FORM GST ADT-02. This report is shared with the taxpayer.
7. Post-Audit Action: If no discrepancy — the matter closes. If discrepancy found — proceedings initiated under Section 73 (normal cases) or Section 74 (fraud/suppression). A Show Cause Notice (SCN) will follow.

Video: GST Audit process — how departmental and special audits work in practice

7. After the Audit Report: Demand, Penalty & Recovery

The audit report is not the end — it is often the beginning of a separate proceedings chain. Depending on what the auditor finds, the following paths are possible:

Section 73 — Non-Fraud Cases

Where the discrepancy does not involve fraud, willful misstatement, or suppression of facts, the officer issues an SCN under Section 73. The taxpayer gets an opportunity to reply. If the tax, interest, and 10% penalty are paid before the SCN, penalties can be reduced significantly. The demand order must be issued within 3 years from the due date of the relevant annual return.

Section 74 — Fraud or Suppression Cases

If the audit reveals fraudulent availment of ITC, suppression of turnover, or deliberate misclassification, proceedings move to Section 74. Here the penalty is significantly higher — up to 100% of the tax due — and the limitation period extends to 5 years. This is territory where a CA’s early intervention and strong written submissions make the biggest difference.

8. CA’s Pre-Audit Checklist for Clients

The 15 working days between the audit notice and commencement are critical. Use this checklist with every client who receives a GST audit notice under Section 65:

• Download GSTR-2B for all months in the audit period and match with purchase register — identify unclaimed or excess ITC
• Reconcile GSTR-1 with GSTR-3B — any differences in outward supply declaration must be explained
• Verify Rule 42 reversal working for exempt + taxable supply clients — months where this was missed must be self-corrected proactively
• Check RCM liability — list all Section 9(3) and 9(4) transactions and confirm GST was paid and ITC subsequently claimed correctly
• Cross-check e-invoicing compliance for applicable months — any missed IRNs for eligible invoices will be flagged
• Reconcile GSTR-9 against monthly returns for the audit year — unexplained differences invite deeper scrutiny
• Confirm all credit notes are properly reflected in GSTR-1 and the buyer has reversed ITC where required
• Check TCS/TDS under GST (Section 51/52) if applicable for e-commerce or government supply clients
• Gather and organise all supporting documents in date-wise order — the auditor’s time is limited and organised records signal credibility
• Identify any voluntary disclosures that can be made before the auditor arrives — proactive correction under Section 73 significantly reduces penalty exposure

9. Real-World Scenario: How One CA Saved a Client ₹18 Lakh in Penalties

Here is a scenario that reflects what many CAs encounter in practice — names changed for confidentiality.

Background: A mid-size textile manufacturer in Surat with annual turnover of ₹12 crore received a Section 65 audit notice for FY 2021-22. The client had substantial exempt sales alongside taxable sales and had been availing full ITC without performing Rule 42 reversals.

What the CA found in 15 days: On pulling the numbers, the CA found that the client had excess ITC of approximately ₹9.4 lakh that should have been reversed under Rule 42. Additionally, two months’ RCM liability on freight charges (GTA services) had not been paid — a further ₹1.1 lakh exposure.

Action taken: Before the audit commenced, the CA filed GSTR-3B amendments to reverse the ITC and paid the RCM along with interest under Section 50. The client voluntarily disclosed these in a covering letter to the audit officer along with a detailed reconciliation statement.

Outcome: Because the discrepancy was self-disclosed and rectified before the audit formally identified it as a finding, the officer proceeded under Section 73 — not Section 74. The 10% penalty (₹1.05 lakh) was applied instead of the 15-100% that would have followed a Section 74 proceeding. Total saving versus the worst-case outcome: approximately ₹18 lakh inclusive of compounded penalty and legal costs.

For the complete statutory text, refer to:

• CGST Act, 2017 — Section 65 and 66 (CBIC official text)
• GST Portal Tutorial — Audit and Assessment procedures (tutorial.gst.gov.in)
• GST Portal — Official notices and forms (gst.gov.in)
• CGST Rules 2017, Rule 101 — Audit procedure (CBIC)

This post connects directly with other guides on this site that are relevant to GST audit preparation:

• GSTR-2B Reconciliation with Purchase Register — critical for ITC audit readiness
• ITC Reversal under Rule 42 — most common audit finding explained
• GSTR-9 Annual Return Filing Guide — reconcile before auditors do
• Reverse Charge Mechanism under GST — Section 9(3) and 9(4) compliance

10. Frequently Asked Questions

Disclaimer: This article is for educational purposes only and reflects provisions of the CGST Act, 2017 as amended. Tax laws are subject to change — always verify with the latest CBIC circulars at cbic.gov.in or consult a qualified GST practitioner before taking any action based on this content. For professional advice on your specific matter, contact our team.