"Despite encouraging recent trends, rates of diet-related disease remain high and are major contributors to inequity of health outcomes in New Zealand," he said.
"There is convincing evidence that dietary changes can profoundly reduce risk but population-based initiatives will be required to facilitate their implementation."
Professor Cliona Ni Mhurchu from the University of Auckland said New Zealand has the third highest levels of obesity in the OECD.
"Our inexorably rising levels of obesity and associated diseases mean we must rethink our approaches to the way we tackle these diseases," Ni Mhurchu said.
The researchers will be presenting the latest evidence that is unique to New Zealand and calling on the Government for strong leadership.
"We urgently need commitment [from the Government and agencies] on new approaches, such as a Government-led reformulation programme to reduce salt, sugar and saturated fats in New Zealand packaged and processed foods."
Another of the symposium organisers, professor Boyd Swinburn from the University of Auckland, said food industry-led "pledges" in the past have not worked.
"Creation of a healthier population food supply requires commitment, strong leadership and legislation by the Government to move this ahead," he said.
The symposium will be opened by Minister of Health David Clark and will feature global perspectives, but also uniquely, New Zealand views from Māori, research and industry.
It starts in Wellington tomorrow.