Indonesia’s Leadership In ASEAN Enlargement – OpEd

 May 28, 2025 

By Simon Hutagalung

Indonesia’s push for the membership of Timor-Leste and Papua New Guinea in the Association of Southeast Asian Nations (ASEAN) highlights Jakarta’s strategic aim to reshape regional dynamics and strengthen its leadership within Southeast Asia.

As the fourth most populous country in the ASEAN bloc and the member with the largest economy, Indonesia is projected to surpass USD 1.4 trillion in nominal GDP by 2025. This gives Indonesia considerable influence in shaping ASEAN’s policy agenda. President Prabowo Subianto’s clear support during the ASEAN Head of State and Government in Kuala Lumpur, Malaysia, for the accession bids of Timor-Leste and New Papua reflects Jakarta’s aim to strengthen ASEAN’s geopolitical position in the face of growing great power competition in the broader Indo-Pacific region. However, despite Indonesia’s diplomatic influence and ambitions for developmental assistance, both states face significant challenges in attaining full membership. Meanwhile, ASEAN must address structural and ideological differences to preserve its cohesion and effectiveness.

Timor-Leste is at the forefront of ASEAN expansion, having secured “in principle” agreement for membership at the 2022 Summit and participating as an observer in various ministerial meetings. Its historical and geographic proximity to Indonesia has fostered extensive bilateral cooperation. In 2023-2024, Jakarta allocated over USD 150 million in development aid to improve Timor-Leste’s road networks and port facilities, as well as providing technical support for public administration reforms.

Despite these efforts, Timor-Leste’s per capita GDP of approximately USD 1,700 in 2025 remains one of the lowest in Asia, compared to the ASEAN average of USD 12,000. The country’s economy is heavily reliant on petroleum revenues, which accounted for nearly 40 percent of government receipts in 2024. This dependence exposes Timor-Leste to the risks of volatile oil prices, while its domestic private sector is still in its infancy, contributing less than 20 percent to GDP. Consequently, Timor-Leste faces challenges in meeting ASEAN’s economic benchmarks for trade and investment liberalization, which require robust infrastructure, diversified industries, and regulatory alignment.

Membership in ASEAN requires Timor-Leste to commit to over 300 multilateral agreements encompassing political-security cooperation, economic integration, and socio-cultural collaboration. Has Indonesia attempted to expedite these processes by providing negotiators and legal experts? However, the administrative burden is significant: Timor-Leste currently has diplomatic missions in only five ASEAN capitals and must establish embassies in all ten member states to comply with ASEAN standards. Additionally, its civil service, which consists of approximately 25,000 employees, needs to be strengthened to manage a wide range of agendas, from the ASEAN Forum Regional to the Intergovernmental ASEAN Commission on Human Rights. Educational attainment also lags: adult literacy stands at 68 percent compared to an ASEAN average of 90 percent, complicating efforts to engage in high-level policy and deliberations, knowledge-sharing networks. 

Papua New Guinea presents a unique set of challenges that test the limits of Indonesia’s vision. Although it shares a 760-kilometer land border with Indonesia, the island of New Guinea, or PNG, is geopolitically aligned with Oceania and has stronger ties to the Pacific Islands Forum. Its GDP per capita is approximately USD 400 in 2025, which is modest compared to the ASEAN median. The country faces uneven development, with rural poverty rates exceeding 35 percent and urban infrastructure deficits hindering both internal cohesion and cross-border trade. Indonesia has implemented border-management assistance programs and security cooperation initiatives to stabilize its provinces along the ASEAN frontier. However, the ASEAN Charter explicitly limits membership to states geographically located in Southeast Asia. Overcoming this legal barrier would require a formal amendment to the Charter, a process that necessitates unanimous approval from all current members, thus exposing differing views on the bloc’s strategic direction.

Reservations among members further complicate PNG’s accession. Singapore and Malaysia have expressed concerns that admitting less-developed economies could dilute the bloc’s economic competitiveness. They fear that integration mechanisms, such as the ASEAN Development Fund, could burden budgets and resources. Meanwhile, Vietnam and Thailand, while supportive of Indonesia’s leadership, worry that admitting PNG might set a precedent for non-Asian Southeast Asian states seeking membership, thereby blurring ASEAN’s core identity. Indonesia has positioned Papua New Guinea’s (PNG) inclusion as a strategic necessity. Integrating PNG would allow ASEAN to effectively monitor and tackle transnational issues such as illegal logging, human trafficking, and maritime boundary disputes impacting Indonesia’s West Papua provinces. In response, Jakarta has formed high-level working groups to align PNG’s legal framework with ASEAN standards. However, further progress is still dependent on achieving a broader consensus.

Indonesia’s advocacy for enlargement within ASEAN reveals deeper institutional challenges. The principle of consensus grants each member a de facto veto over major decisions. While Jakarta can lobby intensively, it cannot override objections from smaller states that fear losing cohesion or being disproportionately influenced by a single power. Additionally, ASEAN’s integration agenda is facing inertia: tariff reduction targets under the ASEAN Trade in Goods Agreement are stalled at 98 percent coverage, digital economy frameworks are unevenly adopted, and non-tariff barriers continue to obstruct cross-border investments. Admitting Timor-Leste and Papua New Guinea would exacerbate these demand complexities, creating a need for more capacity-intensive and extensive dispute-resolution mechanisms.

To conclude, Indonesia’s proactive diplomacy, focused on development through assistance, security cooperation, and advocacy for reform, has created unprecedented momentum for enlargement. However, the final decision depends on ASEAN’s collective will, which is strategically divided due to issues ranging from the crisis in Myanmar to Sino-rivalry in the South China Sea. Therefore, Indonesia must strategically leverage its economic influence, projected to account for 40 percent of ASEAN’s combined GDP by 2025, to support targeted capacity-building programs, incentivize cooperation, and foster consensus. Jakarta should also advocate for incremental integration milestones, such as sectoral dialogue partnerships and enhanced observer roles, allowing aspirant nations to deepen their involvement without assuming immediate full obligations. By doing so, Indonesia can demonstrate that expansion is feasible while maintaining ASEAN’s cohesion and operational resilience. Ultimately, Jakarta’s leadership will play a crucial role in determining whether ASEAN evolves into an inclusive, truly regional forum or reveals an impasse that highlights the limits of unity in the face of ambitious enlargement.

The opinions expressed in this article are the author’s own.

References

• Gomes, R. A. (2025, January 31). Leveraging ASEAN membership for Timor-Leste’s development: Issues and recommendations. Economic Research Institute for ASEAN and East Asia (ERIA). https://www.eria.org/publications/leveraging-asean-membership-for-timor-leste-s-development–issues-and-recommendations
• Pahlepi, J. (2025, March 2). Timor-Leste’s upcoming membership to ASEAN: Clearer guidance needed. Centre for International Law, National University of Singapore. https://cil.nus.edu.sg/blogs/timor-lestes-upcoming-membership-to-asean-clearer-guidance-needed
• The Australian. (2025, May 27). Jakarta calls on ASEAN to make PNG a member. https://www.theaustralian.com.au/world/prabowo-subianto-urges-asean-bloc-to-admit-papua-new-guinea-to-build-global-heft/news-story/0d680410d96c9caac9417402fc1ae9c7

Simon Hutagalung

Simon Hutagalung is a retired diplomat from the Indonesian Foreign Ministry and received his master's degree in political science and comparative politics from the City University of New York. The opinions expressed in his articles are his own.