INTRODUCTION Until 2050, Australia and New Zealand will experience continuing increase in the population aged >65 years. Studying differences in indicators of old-age structure between these countries can inform policymakers. AIM To calculate and analyse indicators of old-age structure for Australia and New Zealand. METHODS Five indicators of old-age structure were calculated: centenarian ratio (number of centenarians per 100,000 people), longevity index (proportion of people aged ≥90 and ≥65 years in the population), longevity level (proportion of 80+/60+ years population), ageing tendency (proportion of people aged ≥60 years in the population) and centenarity index (ratio between the centenarians and the total population ≥90 years). RESULTS All indicators of old-age structure demonstrated an advantageous ageing structure in Australia compared with New Zealand. In addition, the New Zealand Māori and Australian Aboriginal indicators of old-age structure demonstrated a significant disadvantage to these ethnic groups compared with the general population. DISCUSSION Public health policy needs to target ageing in New Zealand as a major goal in advancing the 'Ageing Well' policy advocated by the government.