People who need to carefully monitor fat and sugar content in their food selection may now use a mobile phone app to keep things easy and handy.

The Obesity Policy Coalition says the new mobile app called Traffic Light Food Tracker will enable users to work around the food industry's hesitation in supporting traffic light labelling.

Traffic light labelling marks foods high in fat, sugar and salt with red warnings, while green labels are for healthy options.

Users only have to key in their food item's fat, sugar and sodium quantities and save each item in their "pantry" within the phone app.

Earlier this year, a review of Australia's food labelling laws failed to specifically recommend a mandatory traffic light labeling system for unhealthy food items, saying such a course of action should only be done on a voluntary basis.

The Federal Government is due to respond to the recommendations for compulsory traffic light labelling for packaged food items later this year.

Obesity Policy Coalition spokeswoman Jane Martin says the system has been shown to improve people's eating habits.

"We believe if traffic lights were mandatory on all packaged foods it would guide and empower consumers to make healthier choices for themselves and their families - that's certainly what the evidence shows," she said.

"It has been used in a voluntary capacity in the UK. For a category like ready meals with the traffic lights, sales of the healthy ready meals went up and sales of the unhealthy ready meals went down... Our research shows consumers want to know how much salt, sugar, saturated fat and total fat, is in the products they buy."

Traffic light labels easily give this information in one quick look, and it help shoppers make wise and healthy decisions on food choices.

Melanie McGrice from the Dietitians Association of Australia also says there should be mandatory front-of-pack food labelling on all kinds of food products.

But she stresses legislation, as well as the Traffic Light Food Tracker app, must show to consumers both the nutritional benefits and unhealthy content of each food item.

"From what I've heard there may be a few issues with [the app]. You're never going to find anything that's perfect but I think what's important is we find something that's evidence-based," she said.

"As for which is the way to go, I think we still need a bit more research into the best option."

Earlier this year, Australian Food and Grocery Council spokeswoman Kate Carnell described the traffic light labelling concept as overkill, noting this would mean extra cost to manufacturers, which will be passed on to consumers.

"Already in Australia we have a front-of-pack labelling system on over 4,000 products that consumers are taking to very well, so it seems totally unnecessary," she said.

Diabetes Australia Victoria, the Cancer Council Victoria and the Victorian Health Promotion Foundation (VicHealth) comprise the Obesity Policy Coalition.