A study of some supermarkets in the Wellington area shows that sugary, fizzy drinks are more likely to be discounted than healthy drinks.
The University of Otago research recorded beverage discounts at four Wellington supermarkets in April 2007.
The research was published in the Australian nutrition journal Nutrition and Dietetics this month.
Two of the supermarkets surveyed were in low socio-economic areas and two were in high socio-economic areas.
The results showed unhealthy drinks containing lots of sugar and fat were on special more often than healthy options at all four supermarkets.
The researchers' conclusions include a suggestion to restrict the power supermarkets have over promoting healthy choices by choosing which items to discount.
The study also calls for a nation-wide investigation into how beverages are discounted by supermarkets.