Christine Cabasset, Eric Frecon – Australia and its partners need to monitor the developments in China's engagement with Timor-Leste carefully. Canberra should also, ideally, implement proactive initiatives to strengthen its own relationship with Dili.
Given Chinese interest in controlling choke points in the Indo-Pacific, there are reasons to expect that Beijing will aim to gain influence over the small country, 450 km from the Australian mainland. Namely, Timor-Leste offers significant strategic benefits to China, not least being its proximity to straits that give access to the Indian Ocean.
This is of direct concern to Australia as Timor-Leste's waters are directly adjacent to Australia's exclusive economic zone, and its maritime approaches are close to Australia's north.
Timor-Leste's and Australia's strong relationship is governed by long-standing support, geographical proximity and strategic interest. Indeed, Canberra is Dili's most significant defence partner. After two decades of strained engagement – primarily due to Australia's demand for hydrocarbons and its resistance to negotiating maritime borders until a new treaty was signed in 2018 – Prime Minister Anthony Albanese's first official visit to Dili in early 2026 and the signing of a New Partnership for a New Era reaffirmed the critical role of the bilateral relationship. It also highlighted the common will for a Greater Sunrise gas field joint exploitation to the benefit of Timor-Leste.
Additionally, Timor-Leste's diplomatic engagement in the region, including its accession to the Association of Southeast Asian Nations last October, means that Chinese engagement may not be a short-term concern, but it is of longer-term interest to Australia.
Last year, the president of Timor-Leste raised the possibility of his country's military participating in exercises led by the Chinese military, only if the activity is 'not directed at any perceived hostile entity'. Timor-Leste and other ASEAN members have similar relations with China, namely the rejection of taking sides in great-power competition between the United States and China.
Given China's growing interest in the surrounding waters, maintaining strong relations between Australia and Timor-Leste is vital. Beijing is aware of the significance of the 3,000-metre-deep Ombai and Wetar Straits, located north of Dili. These straits are already critical: five undersea cables run through them. As US-backed cables increasingly avoid the South China Sea due to Chinese interference, the Ombai-Wetar corridor could emerge as a subregional hub for digital infrastructure.
The straits also serve a military function, offering one of the few discreet deep-water transit routes for both Chinese and Australian submarines. For China, these straits represent an alternative gateway beyond the first island chain – alongside the Balabac, Mindoro-Sibutu-Makassar-Lombok route and the Bashi Channel between Taiwan and Luzon – allowing access to the approaches to Australia. Echoing Hu Jintao's 2003 Malacca dilemma, if traditional chokepoints were to be blocked, these waters could become a new sea lane for Beijing.
For these reasons, it would make sense for China to seek opportunities to navigate around, place undersea sensors (as the expertise is available within the Chinese military), map the seabed and collect data regarding the traffic and the composition of the water, enabling more efficient sonar use.
Dili also previously awarded construction contracts to China related to the Tasi Mane petrochemical project on the Southern coast, leading Australia to fear the establishment of a Chinese-controlled port. This is only 450 km away from Darwin, where the lease awarded to the port by the Northern Territory in 2015 to Chinese-owned company Landbridge is likely to be reviewed. Albanese has made it clear that the government wants the port returned to Australian ownership.
Based on the opacity of increasing Chinese engagement in security and maritime affairs, there are a few things Dili can do to protect its sovereign rights. To show its concern, Dili has already organised a 14-day mapping mission with the privately owned US scientific vessel OceanXplorer. Additionally, Dili, which is poorly equipped with just three patrol boats and 250 navy personnel, should continue to diversify its naval partnerships alongside Australia to monitor any potential maritime activity.
This could be a good opportunity for liked-minded partners such as Australia and France to work together. It would follow defence cooperation between France and Timor-Leste, two successive port-of-calls of the Vendemiaire frigate in Dili in 2024 and 2025, and the visit of the French Navy ship Auguste Benebig in February.
Paris can also share its expertise in deep sea warfare (as it got a head start through its Seabed Warfare Strategy), in maritime governance (through its unique model, named 'State Action at Sea') and in anti-submarine warfare. As for the latter, its navy demonstrated its capability along the Indonesian straits during the 2025 La Perouse exercise and in 2023 for hydrographic cooperation off Aceh. In March, it also received its fifth US 6th Fleet award, which rewards the most efficient units in submarine detection and tracking.
Better maritime domain awareness would also contribute to the fight against illegal trafficking. And if partners drop their guard, Australian and East-Timorese fishermen could soon catch Chinese drones in their nets, as has already happened in the Indonesian Makassar Strait and the Philippine Balintang and Luzon Straits.
[Christine Cabasset is an associate and former deputy-director of IRASEC (Bangkok). Eric Frecon is a visiting fellow at ASPI.]