Section 90 of the Constitution of Australia prohibits the States from imposing customs duties and of excise. The section bars the States from imposing any tax that would be considered to be of a customs or excise nature. While customs duties are easy to determine, the status of excise, as summarised in Ha v New South Wales, is that it consists of "taxes on the production, manufacture, sale or distribution of goods, whether of foreign or domestic origin." This effectively means that States are unable to impose sales taxes.