Audit by tax authorities: procedural notice, timeline and consequences for noncompliance with GST records. The Commissioner or authorised officer may audit registered persons, at their business or office, after serving at least fifteen working days' notice. Audits must be completed within three months of commencement of audit, subject to a single extension not exceeding six months for recorded reasons. Officers may require access to books, documents, information and assistance. On completion the proper officer must inform the taxpayer of findings, reasons and rights within thirty days. Detection of unpaid, short paid or erroneously refunded tax or wrongly availed input tax credit may trigger recovery action.