Soft drinks should be taxed in the same way as cigarettes and leaded petrol to boost the budget by $520 million per year and tackle Australia's obesity epidemic, according to a new report.

The supertax, to be applied to the sugar content of non-alcoholic water-based drinks in addition to the GST, would be set at 40 cents per 100 grams of sugar.

Unless it spurred manufacturers to cut the sugar content of their drinks, it would add 80 cents to the price of a 2 litre soft drink, 15 cents to the price of a 375ml can, 14 cents to the price of a 600ml sports drink, and 11 cents to the price of a 250ml energy drink like Red Bull.

The report's principal author, Stephen Duckett, is a former head of the federal Department of Health.