A first-of-its-kind study conducted by the Global Obesity Centre at Deakin University has assessed the nutrition policies of Australia's major supermarkets, finding they could be doing much more to encourage healthy eating.

"Unhealthy diets and obesity are leading contributors to poor health in Australia," lead author Associate Professor Gary Sacks said.

"Tackling the issue requires a comprehensive societal response, including government policy and wide-scale action from the food industry, which includes our supermarkets."

Researchers rated the policies of Woolworths, Coles, Aldi and IGA out of 100 in the review which examined six key areas including nutrition labelling, promotion practices and product accessibility.

The data included publicly available information collected until the end of 2017 plus policy information provided by the retailers.

The information was then assessed using the 'Business Impact Assessment - Obesity and Population Nutrition tool' developed by INFORMAS, a global network of public health researchers that monitor food environments worldwide.

Woolworths ranked the highest, scoring 46 out of 100, while IGA scored just eight points.

"Their food labelling was where they scored pretty well, most of the supermarkets have committed to rolling-out the government's Health Star Rating system that makes it easy to see which products are healthy," Prof Sacks said.

Woolworths also scored "okay" when it came to promoting healthy food, but they "fell down" due to the heavy promotion of unhealthy food, Prof Sacks said.

"The supermarkets are quite vocal about being healthy places to shop but the reality is once you are in the store there is heaps of promotion of unhealthy food," he said.

"The end-of-aisle displays are typically filled with unhealthy products, it's just chocolate and soft drinks at the checkouts; so it's just really hard to stick to a nice healthy basket of food when you are surrounded by all of that."

Claire Peters, Managing Director Woolworths Supermarkets, said the company had introduced many initiatives to help customers fill their trolleys with healthier foods, including the Free Fruit for Kids Program.

"While the report highlights some of the progress we have made, we do acknowledge there is more we can do," Ms Peters said in a statement.

Coles also defended its commitment to providing customers with "healthy, Australian-grown food".

"We note that the report does not take account of the important role of exercise in a healthy lifestyle,"a Coles spokesperson said in a statement.

But it's the checkouts and promotion of junk food that public health experts want the supermarkets to target.

"Several UK supermarkets have committed to provide healthy checkouts, with no chocolates, soft drinks or lollies on display," said Prof Sacks.

Australian Associated Press