Australia and East Timor will on Tuesday sign a treaty at the United Nations to end a dispute over their maritime border and potentially unlock billions of dollars in revenue from offshore oil and gas.
UN Secretary-General Antonio Guterres will preside over the signing ceremony to be attended by Australian Foreign Minister Julie Bishop and Deputy Prime Minister Agio Pereira of East Timor, Asia's youngest nation which joined the United Nations in 2002.
The treaty could provide a major boost to East Timor's struggling economy with an agreement on sharing revenue from the Greater Sunrise oil and gas fields, worth between $40 and $50 billion.
Following a final round of negotiations in Kuala Lumpur last month, Australia and East Timor agreed to the treaty that delimits the maritime boundary between them in the Timor Sea and establishes revenue-sharing arrangements.
East Timor in 2016 dragged Australia before the Permanent Court of Arbitration, the world's oldest arbitration tribunal, based in The Hague, after contesting a previous deal signed in 2006.
Dili wanted that treaty, which also covered the vast Greater Sunrise fields, torn up after accusing Australia of spying to gain commercial advantage during the negotiations.
As the dispute escalated, a group of energy companies including Australia's Woodside, ConocoPhillips, Shell and Osaka Gas decided to mothball plans to develop the Greater Sunrise fields.
In January last year, the two neighbors announced that a new pact would be negotiated through the arbitration court.
Details of the revenue-sharing arrangements have not been released, but a statement from the arbitration court last month said the shares "will differ depending on downstream benefits associated with the different development concepts" for the gas fields.
Discovered in 1974, Greater Sunrise is located 150 kilometers (93 miles) southeast of East Timor and 450 kilometers northwest of Darwin.