BACKGROUND: Papua New Guinea (PNG) has one of the highest burdens of HIV and syphilis in pregnancy in the Asia-Pacific region. Timely and effective diagnosis can alleviate the burden of HIV and syphilis and improve maternal and newborn health. Supply-side factors related to implementation and scale up remain problematic, yet few studies have considered their impact on antenatal testing and treatment for HIV and syphilis. This study explores health service availability and readiness for antenatal HIV and/or syphilis testing and treatment in PNG. METHODS: Using data from two sources, we demonstrate health service availability and readiness. Service availability is measured at a province level as the average of three indicators: infrastructure, workforce, and antenatal clinic utilization. The readiness score comprises 28 equally weighted indicators across four domains; and is estimated for 73 health facilities. Bivariate and multivariate robust linear regressions explore associations between health facility readiness and the proportion of antenatal clinic attendees tested and treated for HIV and/or syphilis. RESULTS: Most provinces had fewer than one health facility per 10 000 population. On average, health worker density was 11 health workers per 10 000 population per province, and approximately 22% of pregnant women attended four or more antenatal clinics. Most health facilities had a composite readiness score between 51% and 75%, with urban health facilities faring better than rural ones. The multivariate regression analysis, when controlling for managing authority, catchment population, the number of clinicians employed, health facility type and residence (urban/rural) indicated a weak positive relationship between health facility readiness and the proportion of antenatal clinic attendees tested and treated for HIV and/or syphilis. CONCLUSION: This study adds to the limited evidence base for the Asia-Pacific region. There is a need to improve antenatal testing and treatment coverage for HIV and syphilis and reduce healthcare inequalities faced by rural and urban communities. Shortages of skilled health workers, tests, and medicines impede the provision of quality antenatal care. Improving service availability and health facility readiness are key to ensuring the effective provision of antenatal care interventions.