Alcohol is a leading cause of morbidity and mortality in New Zealand. Restricting the availability of alcohol is considered one of the most effective measures to reduce alcohol-related harm; however, effects have largely been extrapolated from evidence assessing the liberalisation of availability. In New Zealand, a rare opportunity exists to assess the effects of liquor licensing restrictions aimed to reduce the availability of alcohol (including restricted trading hours and outlet density). The study aim is to assess how the availability of alcohol is related to police and ambulance call outs and alcohol-involved crashes prior to and following the policy changes. A spatial model will be developed that overcomes limitations with previous models and will measure alcohol availability to better reflect its key underlying dimensions. This study will provide new knowledge about impacts of alcohol policy change and contribute to national and international efforts to reduce alcohol-related harm.