Refund of tax: procedure and conditions for claiming GST refunds, eligibility, documentation, withholding and interest rules. Section 54 prescribes timelines, forms and documentary evidence for claiming a refund of tax, limits refund of unutilised input tax credit to specified situations (notably zero rated supplies and where input tax rates exceed output tax rates), excludes refunds where export duty applies or supplier has claimed integrated tax refund, permits provisional refunds for certain zero rated claims, requires proper officer determination within a statutory period, and allows withholding or deduction of refunds where returns are defaulted, liabilities exist, or revenue is at risk.