In 1950 a Board of Trade was established under the Board of Trade Act and one of its main functions was to review the tariff, which had been only slightly changed since 1933. The Board began by holding hearings from industry and some changes to the tariff were consequently made. In 1956, however, the Board began a review of the whole of the tariff. All interested parties could give evidence and the Board's recommendations to the Government in 1957 were based on this evidence and its own investigations. Some amendments were made to the existing tariff in 1960, but it was not until 1961 that a completely new tariff, based on the rates of duty recommended by the Board, was introduced, to apply from July 1962.

The introduction of the 1962 tariff represented a notable departure from the usual policy of introducing tariff changes. For the first time, a new tariff was introduced and made public before the date on which it was to come into force. This modification of a long-standing policy was dictated by the form of the new tariff and the need to give businessmen time to study it before it came into effect.

Though the tariff had been revised many times, there had been no basic modification in the form of the tariff for 40 years or more. The tariff was out of date and, having grown piecemeal, it lacked a sound technical basis on which the changes necessary to meet the needs of modern trade could be made. The nomenclature adopted in 1962 was that of the United Nations Standard International Trade Classification (revised), which lists the goods of world commerce systematically on economic significance. The text of the main headings and items is derived from the Brussels Tariff Nomenclature of the Customs Cooperation Council, and the contents of these headings is, therefore, determined by the rules of classification of the Brussels Tariff Nomenclature. The new nomenclature is designed to give, in a single document, a scientifically ordered classification of goods both for tariff and for statistical purposes.

For many years duty had been charged on goods subject to ad valorem duties on the current domestic value in the country of export plus 10 per cent. The additional 10 percent was probably originally imposed for the purpose of bringing the value for duty to an assessed “cost, insurance, freight” value. This practice had been in force in some other countries, but for many years New Zealand had been the only one to continue it. During the 1956–57 review of the tariff, the Board of Trade also examined various bases for the valuation of goods for duty, including the now commonly used c.i.f. basis, but concluded that charging duty on the current domestic value without the addition of 10 per cent had distinct advantages for New Zealand. With the introduction of the new tariff in 1962, the addition of the 10 per cent to the current domestic value was discontinued. To compensate for the lower value for duty, some, but not all, rates of duty were increased by approximately 10 per cent to yield the same amount of duty on the goods concerned.

It had been the practice in the case of goods imported from a Commonwealth country having a unit of currency in pounds to charge duty on the current domestic value of the goods expressed in the currency of the country concerned. The amount of duty paid in £(N.Z.) on goods imported from a Commonwealth country whose pound unit of currency had been depreciated in relation to sterling, was consequently higher than that paid on goods of equal value in £(N.Z.) which had been imported from Britain or another Commonwealth country having a pound unit of currency at par with sterling, the ad valorem rate of duty being the same for imports from both countries. Australia, Fiji, and Tonga had been affected by this procedure, which was now changed with the introduction of the new tariff. Today the value of all goods is converted to New Zealand currency before duty is assessed.