Officially known as the Treaty between Australia and the Republic of Indonesia on the zone of cooperation in an area between the Indonesian province of East Timor and Northern Australia, the Timor Gap Treaty is a treaty between the governments of Australia and Indonesia. The signatories to the treaty were then Australian Foreign Affairs Minister Gareth Evans and then Indonesian Foreign Minister Ali Alatas. The treaty was signed on December 11, 1989 and came into force on February 9, 1991.
It provided for the joint exploitation of petroleum resources in a part of the Timor Sea seabed which were claimed by both Australia and Indonesia.
The portion of the seabed was known as the Timor Gap as it formed a break or gap in the Australia-Indonesia maritime border which had been earlier agreed to because Portugal, the administering power of East Timor, did not wish to participate in a separate round of boundary negotiations as they were already under discussion at the Conference on the Law of the Sea. After the Indonesia invasion and annexation of the colony in 1975–1976, East Timor was made a province of Indonesia and both Australia and Indonesia began negotiations to solve issues arising over claims to the seabed in the area.
Less than two weeks after the treaty came into force, Portugal instituted proceedings against Australia at the International Court of Justice. As Portugal was still recognized by the U.N. as the lawful administering power of East Timor, Portugal requested to dispute the lawfulness of Australia's negotiations as a party to the Timor Gap Treaty on behalf of the people of East Timor. The court ruled that it could not adjudicate the dispute as it would require the court to rule upon the lawfulness of Indonesia's annexation of East Timor, a decision that could not be made, nor could it become binding, without the consent of Indonesia. the court ruled 14 to 2 with Judge Weeramantry and Judge Skubiszewski dissenting.
Judge Skubiszewski condemned the ruling of the court, stating that his primary opposition to the ruling was that, "recognition of annexation erodes self-determination." And that the courts adherence to legal correctness alone had been to the detriment of justice and was, "cause for concern."
The treaty was no longer in force when East Timor seceded from Indonesia in 1998. A new treaty to replace the Timor Gap Treaty was negotiated, resulting in the Timor Sea Treaty.