The main objective of the Norwegian Customs is to prevent unlawful imports and exports and ensure correct declarations and payment of customs and excises duties. By means of its controls the Norwegian Customs reveals irregularities and breaches of the rules. As the controls, such as company audits, are costly, not all firms are controlled. Hence, the controls only reveal parts of the unpaid and undeclared duties and taxes.

Based on historical control data we have been able to present an estimate of the total amount of unpaid and undeclared duties and tax. The study was limited to import of alcohol-free beverages, but may in principle be applied to any kind of duty or tax.