A major challenge to sustainable development of peaceful societies around the world, particularly in developing countries, is represented by several criminal activities and tax-related illicit practices which are at the origin or associated with illicit financial flows (IFFs). Combatting illicit financial flows has been recognized as a crucial component of the campaign to promote peace, justice and strong institutions, as the United Nations set out in Goal 16 of its 2030 Agenda for Sustainable Development. Despite the urgency to limit the drain of financial resources from developing societies, the monitoring of IFFs has been limited due to a lack of a consolidated statistical methodology to measure them. As custodian agencies of SDG indicator 16.4.1, UNODC and UNCTAD have taken action to develop a global and comprehensive statistical methodology to measure the monetary value of inward and outward IFFs. The statistical and conceptual framework to estimate IFFs through a disaggregated, bottom-up approach has been developed and the methodology to estimate selected criminal and tax-related activities is currently being tested in selected countries of Latin America and Africa. However, to ensure robustness and global validity, the methodology testing process needs to expand its geographical scope to other areas by including the Asia-Pacific region, which faces different IFF-related vulnerabilities and challenges. In order to achieve this goal, the implementing partners will engage with national statistical offices, national institutions and government agencies to review the statistical methodology, expand it to include relevant IFF-related activities, and test the methodology though data availability assessment, data collection and production of IFFs statistics in selected countries of this region. Moreover, implementing entities will partner with selected national statistical systems to establish sustainable processes of data collection and production of IFF-related statistics through capacity building activities, including by raising awareness among political institution to promote a long-term engagement in the statistical measurement and monitoring of IFFs.