A new mobile phone application that helps track fat and sugar content in food has been launched in Melbourne today.

The Obesity Policy Coalition says the new Traffic Light Food Tracker will allow shoppers to bypass the food industry's reluctance to support traffic light labelling.

Traffic light labelling puts red warnings on foods high in fat, sugar and salt, and green labels on healthy options.

Users can enter the fat, sugar and sodium quantities in their food items and save each item in their "pantry" within the phone app.

Earlier this year, a review of Australia's food labelling laws failed to recommend a mandatory traffic light system for unhealthy foods, saying the system should only be implemented on a voluntary basis.

The Federal Government is due to respond to the recommendations for compulsory traffic light labelling 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 provide this information at a glance, and help shoppers sort the fat from the fiction."

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

But she says legislation, as well as the Traffic Light Food Tracker, needs to show 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 plan as overkill, saying she was concerned by the cost to manufacturers.

"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.

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