Auxiliary customs duty on specified goods based on customs valuation; payable in addition to existing customs duties. Auxiliary customs duties are levied on goods in the Customs Tariff First Schedule as an additional duty computed by reference to the goods' value determined under the Customs Act; such auxiliary duties are payable in addition to existing customs duties and, insofar as practicable, the Customs Act's provisions and its rules on levy, collection, refunds and exemptions apply to these auxiliary duties, with transitional saving and cessation consequences governed by the General Clauses Act.