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Public International Law


What is a Treaty?

Treaties are the principal source of Public International Law. 

The Vienna Convention on the Law of Treaties defines a ‘treaty’ as ‘an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation’ (Article 2(1)(a)).

A treaty is an agreement between sovereign States (countries) and in some cases international organisations, which is binding at international law. An agreement between an Australian State or Territory and a foreign Government will not, therefore, be a treaty. An agreement between two or more States will not be a treaty unless those countries intend the document to be binding at international law.

Treaties can be bilateral (between two States) or multilateral (between three or more States). Treaties can also include the creation of rights for individuals.

Treaties are commonly called 'agreements', 'conventions', `protocols' or `covenants' , and less commonly `exchanges of letters'. Frequently, `declarations'  are adopted by the UN General Assembly. Declarations are not treaties, as they are not intended to be binding, but they may be part of a process that leads ultimately to the negotiation of a UN treaty. Declarations may also be used to assist in the interpretation of treaties.


Finding Treaties


Drafting History Documents - Travaux Preparatoires

Travaux Préparatoires are official documents recording the negotiations, drafting, and discussions during the process of creating a treaty. These documents may be consulted and taken into consideration when interpreting treaties (Vienna Convention on the Law of Treaties)

To find Travaux Préparatoires:


Treaties to which Australia is a party

The Australian Treaty Database (open access on the DFAT website) can be searched by subject and lists all bilateral and multilateral treaties to which Australia is a party, as well as information about the treaty process and adoption into domestic law.

The Australian Treaty Series website (open access on AustLII) lists all treaties to which Australia is a party and links to the full text - the treaties are listed chronologically and can also be searched by subject. In addition the Australian Treaties Library on AustLII links to other treaty resources such as links to treaties not yet in force, treaties under negotiation, and information about the adoption of treaties into domestic law - both the process and binding nature of the rights and obligations created by the treaty.


The Law of Treaties

The 1648 Peace Treaties of Westphalia established the framework for modern treaties and recognised the right of the sovereign to govern free from outside interference. 

The Vienna Convention on the Law of Treaties is the UN agreement that codifies the rules that guide treaty relations between States. The Convention provides an international legal framework for these relations in times of peace (the effect on treaties of the outbreak of hostilities between States is explicitly excluded from the reach of the Convention). This framework includes the rules on the conclusion and entry into force of treaties, their observance, application, interpretation, amendment and modification, and rules on the invalidity, termination and suspension of the operation of treaties. By providing this legal framework, the Convention promotes the purposes of the UN set forth in its Charter, including the maintenance of international peace and security, the development of friendly relations between states and the achievement of cooperation among nations. 

The treaty text may provide for the manner by which it takes effect. Generally, treaties will enter into force when it has been signed and ratified by a certain number of parties. Parties to a treaty may ratify a treaty with reservations or other declarations unless the terms of the treaty place restrictions on those actions. A reservation is a country's attempt to modify certain terms of the treaty, as it applies between itself and other countries.

Multilateral treaties are published in sets such as the United Nations Treaty Series (UNTS). Only treaties deposited with the UN Secretary-General become part of the UNTS. Although most multilateral (and many bilateral) treaties are deposited with the UN as a matter of course, states are under no specific obligation to do so. A good source of information on the role of the UN as a treaty depository is the Summary of Practice of the Secretary-General as Depository of Multilateral Treaties on the UN website. 


Treaty information in online Encyclopaedias


Citing Treaty Series - AGLC4 Style

If a treaty is included in a treaty series, the treaty series should be cited rather than eg: the UN document number. Treaties are often included in several treaty series. According to Chapter 8.4 of the Australian Guide to Legal Citation, treaties should be cited in the following preferential order:


Treaties Books & e-books

A selection of print and e-books held by the Law Library is listed below. More books on treaties can be found by searching the catalogue or browsing the shelves at KC 330.          


Open Access Articles on SSRN


Treaty Research Guides & Tutorials