Australia
Australia has one of the largest maritime areas in the world, established by its continental shelf claims and by agreement with all of its other maritime neighbours, including Indonesia, Papua New Guinea, France (New Caledonia and Kerguelen Islands), Solomon Islands and New Zealand. However, Australia has so far been unwilling to enter into negotiations with Timor-Leste for a permanent maritime boundary, which represents just 2% of a complete Australian maritime boundary.
The early days of Timorese nationhood and Australia’s carve-out
Between the historic vote for independence in 1999 and the restoration of independence in May 2002, the United Nations was responsible for administrating East Timor, as Timor-Leste was known at the time. During this transitional period, in July 2001 Australia and the United Nations Transitional Administration in East Timor (UNTAET) signed a resource-sharing arrangement in the Timor Sea.
The agreement purported to give Australia rights over resources extending up to the Timor Trough, around 50 nautical miles from Timor-Leste’s shores – far beyond what Australia would have been entitled to under international law if a maritime boundary was drawn by applying the equidistance / relevant circumstances approach.
In March 2002, just two months before Timor-Leste’s independence was restored, Australia withdrew from the maritime boundary jurisdiction of the International Court of Justice and the International Tribunal for the Law of the Sea. This meant the new nation of Timor-Leste could not ask an international court to decide where an equitable boundary would lie under international law in the Timor Sea if it was unable to reach agreement with Australia.
The new nation of Timor-Leste signed the Timor Sea Treaty with Australia on its first day of independence, 20 May 2002.
Australia’s alleged espionage and seizure of Timor-Leste’s documents
Australia and Timor-Leste then negotiated additional treaties to set terms for revenue-sharing and regulatory control in the Joint Petroleum Development Area and in the Greater Sunrise field which extended into waters claimed by Australia under the outdated continental shelf theory. Between 2004 and 2006 Timor-Leste and Australia negotiated the terms of the Treaty on Certain Maritime Arrangements in the Timor Sea (CMATS) and the Agreement between the Government of the Democratic Republic of Timor-Leste and the Government of Australia relating to the Unitisation of the Sunrise and Troubadour Fields (Unitisation Agreement).
After obtaining evidence of an espionage operation by Australia during CMATS negotiations, Timor-Leste challenged the validity of CMATS and the amended Timor Sea Treaty at the Permanent Court of Arbitration.
On 3 December 2013, Australian security intelligence officers seized Timor-Leste’s documents and data which were in the possession of one of Timor-Leste’s lawyers, including legal documents relating to the arbitration which was underway between the two States. The Australian Government refused to return these materials. Timor-Leste commenced proceedings in the International Court of Justice seeking a declaration that the seizure and detention of such materials was unlawful.
On 3 March 2014, the International Court of Justice handed down interim orders which went beyond Timor-Leste’s expectations and ordered Australia not to interfere in the communications between the Timor-Leste Government and its legal advisers. Australia has since recognised the need for all States to respect the confidentiality of communications between States and their legal advisers.
In September 2014, Timor-Leste and Australia agreed to suspend both the espionage arbitration and document seizure case for six months in order to reach an amicable settlement of their dispute. No agreement was reached in that time. While Timor-Leste sought to engage with Australia in structured negotiations on permanent maritime boundaries, Australia expressed its unwillingness to discuss the permanent maritime boundary issue.
On 12 May 2015, over one year after the raid on Timor-Leste’s legal offices, Australia returned the seized documents and data. Having achieved this positive result, Timor-Leste discontinued the document seizure proceedings in the International Court of Justice.

The hearing at the International Court of Justice in The Hague between Timor-Leste and Australia. Source: United Nations