Nutrient security refers a country’s ability to provide a food supply that meets the energy, macronutrient, and micronutrient requirements of its population. While Australia is generally considered food secure(1), micronutrient deficiencies persist in the population(2). To date, no studies have comprehensively estimated or assessed Australia’s nutrient security. This study aimed to evaluate the adequacy of Australia’s food supply in meeting population nutrient requirements and the extent of reliance on imported foods to do so. The national food supply in 2019 was estimated using Food and Agriculture Organization (FAO) Food Balance Sheets and data from the 2011–2012 National Nutrition and Physical Activity Survey (NNPAS). The supply of energy, macronutrients, and micronutrients was estimated using the Australian Food Composition Database (AUSNUT). The resulting estimates of nutrient supply were compared to population-weighted Nutrient Reference Values (NRVs). To assess reliance on imports, nutrient supply from domestically produced foods were estimated and compared to population requirements. In 2019, Australia’s food supply exceeded population energy requirements by 23%. The estimated supply of protein and essential fatty acids, including linoleic acid, α-linolenic acid, and long-chain omega-3s, was more than double the population’s needs. The supply of dietary fibre was estimated to meet only 82% of the population requirements. The supply of micronutrients met most population requirements, except for calcium, which was estimated to meet 99% of the population’s needs. Imports contributed to meeting population requirements for energy, calcium, iron, and magnesium. Australia’s 2019 food supply was broadly sufficient in meeting national nutrient requirements. However, shortfalls in dietary fibre and calcium, along with reliance on imported foods for several key nutrients highlight areas of potential vulnerability in the national food system. Continued monitoring and further research are needed to ensure long-term nutrient security beyond basic food availability.