Researchers at the Australian National University have modelled the effects of charging a 20 per cent tax on sugary soft drinks on the suburbs of Canberra, finding people living in the far south in Conder, Gilmore, and Banks and the outer north spend the most on the drinks and would be hardest hit.

People living in Lyneham, Campbell and Griffith wouldn't feel the pinch, spending much less of their weekly income on sugary drinks.

Lower socio-economic suburbs of Charnwood, Richardson and Gilmore not only spend a higher dollar figure on sugary drinks, but also a larger share of their income, with a 20 per cent sugar tax on soft drinks expected to hit people there by almost $90 a year on average.

The Australian Medical Association and other health bodies have long campaigned for a sugar tax to reduce the risks of obesity, heart disease and diabetes, and a similar tax has already been introduced in Britain.

Bio-statistician at the Research School of Population health Dr Alice Richardson said a tax on consumption could both change people's habits as well as encourage companies to change the ingredients of their products to avoid the tax.

"Broader research around introducing a sugar tax is that it is good for population health and research from across the board would support the introduction of a sugar tax like we see in a large number of countries," Dr Richardson said.

Dr Richardson said the research, which she undertook with Dr Aparna Lal, showed the importance of measuring the effects of a policy across the whole geography, not just of the ACT, but Australia.

"It's certainly true that our models show the impact is quite uneven," Dr Richardson said.

Associate professor Ben Phillips, who also contributed to the modelling, said the tax was regressive in the way that it affects people with lower incomes harder, but that like taxes on tobacco, it is targeted that way for a reason.

"The point is to get people who are spending more on that product and the hope is they will consume less of that product and so in that sense it is well targeted," he said.

"Hopefully they will spend less on sugary drinks and more on healthier options."

Mr Phillips said the research combined census data with a detailed household expenditure survey by the Australian Bureau of Statistics to make the projections about spending across the ACT and any effect a sugar tax would have.

While many industry bodies have called for the measure, both major parties have labelled the idea a fizzer - Labor because it is a regressive tax, and the Coalition is reluctant to dictate what people should eat and drink.