Audit powers by tax authorities allow inspection, require documents and can trigger reassessment or recovery proceedings. The Commissioner or an authorised officer may audit any registered person at business premises or office after serving notice not less than fifteen working days. Audit must be completed within three months of commencement, subject to a written extension by the Commissioner for up to six further months; commencement is when records are made available or audit actually begins. Officers may verify books, require information and assistance. On conclusion the proper officer must notify the audited person of findings, rights, obligations and reasons within thirty days. Detection of tax deficiencies or wrongly claimed input tax credit may lead to statutory assessment or recovery action.