Research shows New Zealand is lagging behind Australia in dealing with the obesity epidemic.
The School of Population Health at the University of Auckland has released figures which put the cost of obesity at between $722 million and $849 million a year in health care costs and lost productivity.
Professor Boyd Swinburn said a recent comparison shows Australia and New Zealand have similar problems but Australia is doing more to address the issue.
Professor Swinburn said both countries have struggled to reduce junk food advertising but Australia has removed GST on fruit and vegetables, and invests millions on reducing obesity in the workforce.
He said New Zealand governments have taken very little action.
Researchers say an estimated 35% of the New Zealand population aged over 15 are overweight, while 25.4% are obese. They say obesity has been well established as a key risk factor for major chronic illnesses such as cardiovascular diseases, Type 2 diabetes and some cancers.