The free trade area and the customs union deal with both tariffs and trade. However, they differ in many respects. Critics also argue that free trade agreements do not promote trade liberalization as effectively as multilateral agreements. Customs Union Customs UnionA customs union is an agreement between two or more neighbouring countries to reduce trade barriers, reduce or abolish tariffs and remove quotas. These unions have been defined in the General Agreement on Tariffs and Trade (GATT) and are the third stage of economic integration. It also allows the free movement of imports within the zone and among its members. For example, goods from a third country imported by a member of a customs union may also be imported duty-free into other EU countries. The second way of looking at free trade agreements as public goods is related to the growing trend that they are “deeper”. The depth of a free trade agreement relates to the additional types of structural policies it covers.
While older trade agreements are considered more “flat” because they cover fewer areas (for example. B tariffs and quotas), recent agreements cover a number of other areas, ranging from e-commerce services and data relocation. Since transactions between parties to a free trade agreement are relatively cheaper than those with non-parties, free trade agreements are considered excluded. Now that deep trade agreements will improve the harmonization of legislation and increase trade flows with non-parties, thereby reducing the exclusivity of free trade agreements, next-generation free trade agreements will take on essential characteristics for public goods.  These agreements between three or more countries are the most difficult to negotiate. The larger the number of participants, the more difficult the negotiations. They are, by nature, more complex than bilateral agreements, insofar as each country has its own needs and requirements. In the past, there have also been allegations that free trade agreements have been concluded for foreign policy purposes and not for bilateral economic purposes. New Zealand is working to introduce mechanisms to improve communication and consultation in order to resolve access to trade issues in an objective and scientific manner, which will enable us to take the necessary measures to protect the lives or health of our human beings, animals and plants, provided that such measures do not conflict with the WTO agreement on the application of health and plant health measures. A fundamental principle for New Zealand is that any outcome in terms of services and investment must protect our government`s right to regulate for legitimate public policy purposes. Free trade agreements can facilitate visa access for New Zealand businessmen and our trading partners, which supports the development of our trade and economic relationships.
In general, trade diversion means that a free trade agreement would divert trade from more efficient suppliers outside the zone to less efficient suppliers within the territories. Whereas the creation of trade implies the creation of a free trade area that might not otherwise have existed. In any case, the creation of trade will increase a country`s national well-being.  As soon as the agreements go beyond the regional level, they need help. The World Trade Organization intervenes at this stage. This international body contributes to the negotiation and implementation of global trade agreements. Currently, the North American Free Trade Agreement (NAFTA) between the United States, Canada and Mexico is the largest free trade area in the world and produces $17 trillion in goods and services $US. A free trade agreement between two countries or a group of countries can be used to define the rules on how countries deal with each other when it comes to doing