On 1 June 2026, the GST e-invoicing mandate expands to cover all works contract invoices, regardless of turnover threshold. This aligns with the phased rollout that began with B2B supplies in 2021 and extends to all B2B and B2C transactions.
For infrastructure contractors, project developers and civil works service providers, this is a hard compliance date. Non-adoption attracts penalties under section 122 of the CGST Act 2017 and may result in input tax credit (ITC) denial. We examine the scope, system requirements, and critical action items for June 2026 readiness.
Market signals
The GST e-invoicing system (IRP, via the GSTN portal) now mandates electronic invoicing for all works contract supplies, including sub-contracts and supply-plus-works arrangements. No turnover exemption applies after the deadline.
Input tax credit is now allowed only against valid e-invoices generated through the authorised IRP. Manually created or non-standard JSON invoices risk ITC denial during GST audit and assessment.
E-invoices are transmitted live to GSTN; GSTR-1 is auto-populated from the IRP ledger. Contractors must reconcile their invoice generation with monthly GSTR-1 filing to avoid mismatch notices and demand.
Under sections 31 and 34 of the CGST Act 2017, GST officers may deny ITC and levy penalties of up to 25% of tax short-paid if e-invoicing is not complied with. The GSTN (Goods and Services Tax Network) operates the authorised Invoice Registration Platform (IRP); all invoices must be generated via a certified IRP or the GSTN portal. For contractors operating as principals or sub-contractors, non-compliance exposes both the invoice issuer and the recipient to audit action. Vinayakam Consultants helps infrastructure entities map their works contract invoicing workflows to the e-invoicing schema, validate JSON compliance, integrate accounting software with IRPs, and prepare for GSTN audit trails — ensuring ITC eligibility and avoiding downstream penalties.
Your action checklist
- Audit your current invoicing system and confirm whether it is integrated with a GST-authorised Invoice Registration Platform (IRP); if not, migrate to a compliant IRP or the GSTN portal by 31 May 2026.
- Map all works contract line items (labour, materials, sub-contracts, design fees) to GST HSN codes and ensure tax rates and ITC eligibility are correctly coded in your e-invoice JSON schema.
- Test end-to-end e-invoice generation, transmission to GSTN, and GSTR-1 auto-population with a sample invoice in April–May 2026; correct any system gaps before the June mandate takes effect.
- Brief your finance and project teams on the new e-invoice workflow, retention requirements (5 years), and the audit trail implications; establish a process to cross-verify GSTR-1 auto-populated data against your invoice ledger monthly.
Frequently asked questions
All works contract invoices must be GST e-invoiced from 1 June 2026 onwards, regardless of turnover threshold. Non-compliance attracts penalties under section 122 CGST Act 2017 and ITC denial.
ITC is allowed only against valid e-invoices generated through authorised IRP via GSTN portal. Manually created or non-standard JSON invoices risk ITC denial during GST audit.
GST officers may deny ITC and levy penalties up to 25% of tax short-paid under sections 31 and 34 CGST Act 2017 for non-compliance with e-invoicing mandate.