Search and seizure: tax officers may enter, seize and retain assets and documents to secure undisclosed income liabilities. Search and seizure provisions authorise designated tax officers to enter and search premises, break open receptacles, seize and mark books, documents and assets suspected to represent undisclosed income, examine persons on oath, requisition assistance, and serve restraint orders. After hearing and prescribed enquiry, and with Commissioner approval, the Income-tax Officer must make a summary estimation of undisclosed income, compute tax and related liabilities, retain assets sufficient to satisfy those liabilities while releasing the remainder, and subject retained assets to application, sale and return rules with interest payable on amounts retained beyond liabilities.