Government alcohol monopolies were created in North America and Scandinavia to limit health and social problems. The Swedish monopoly, Systembolaget, reports to a health ministry and controls the sale of all alcoholic beverages with > 3.5% alcohol/volume for off-premise consumption, within a public health mandate. Elsewhere, alcohol monopolies are being dismantled with evidence of increased consumption and harms. We describe innovative modelling techniques to estimate health outcomes in scenarios involving Systembolaget being replaced by 1) privately owned liquor stores, or 2) alcohol sales in grocery stores. The methods employed can be applied in other jurisdictions and for other policy changes.Impacts of the privatisation scenarios on pricing, outlet density, trading hours, advertising and marketing were estimated based on Swedish expert opinion and published evidence. Systematic reviews were conducted to estimate impacts on alcohol consumption in each scenario. Two methods were applied to estimate harm impacts: (i) alcohol attributable morbidity and mortality were estimated utilising the International Model of Alcohol Harms and Policies (InterMAHP); (ii) ARIMA methods to estimate the relationship between per capita alcohol consumption and specific types of alcohol-related mortality and crime.Replacing government stores with private liquor stores (Scenario 1) led to a 20.0% (95% CI, 15.3-24.7) increase in per capita consumption. Replacement with grocery stores (Scenario 2) led to a 31.2% (25.1-37.3%) increase. With InterMAHP there were 763 or + 47% (35-59%) and 1234 or + 76% (60-92%) more deaths per year, for Scenarios 1 and 2 respectively. With ARIMA, there were 850 (334-1444) more deaths per year in Scenario 1 and 1418 more in Scenario 2 (543-2505). InterMAHP also estimated 10,859 or + 29% (22-34%) and 16,118 or + 42% (35-49%) additional hospital stays per year respectively.There would be substantial adverse consequences for public health and safety were Systembolaget to be privatised. We demonstrate a new combined approach for estimating the impact of alcohol policies on consumption and, using two alternative methods, alcohol-attributable harm. This approach could be readily adapted to other policies and settings. We note the limitation that some significant sources of uncertainty in the estimates of harm impacts were not modelled.