New Zealand Health officials have suggested that it be made illegal to sell junk food to children. They want a ban written into a new health law to meet concerns about child obesity.

A minimum legal age for being able to eat such food is one of a number of proposed ideas in a Ministry of Health document that aims to limit children's access to food considered to be unhealthy. Other possibilities include limitations on the number, size and location of companies selling certain types of food.

Spokeswoman Robyn Toomath, a consultant endocrinologist at Wellington Hospital and president of the Society for the Study of Diabetes, said the group believed regulation and legislation was urgently needed.

"We have to stop the kids from gaining weight. We have to take a deep breath and say what are the significant factors influencing our children in this epidemic."

Her group's main aims were to stop advertising directed at children and stop schools selling junk food.

The group also wants controls on the quality of food sold within 1km of a school.

"What the heck are we doing selling soft drinks, fruit drinks, chips and pies, sweets and chocolates in schools?" said Dr Toomath.

"These are the foods that are contributing to obesity because they are calorie dense and nutrient poor, it's about time we started getting serious about it and stopped promoting them to children in schools".

"In the long term, they are what will be required."

Restaurant Brands, the company that operates KFC, Pizza Hut and Starbucks in New Zealand, is fighting the proposals.

Chief executive Jim Collier said obesity was a lifestyle disease and needed to be addressed as such.

"We don't think restricting access will address the issue that it is a lifestyle disease."

The discussion document prompted the Advertising Standards Authority to hold a symposium on obesity.

Executive director Glen Wiggs said the authority did not believe there was a link between advertising of food and obesity.

The symposium was boycotted by health groups, such as the Cancer Society, the Heart Foundation, and Diabetes NZ because they believed it was being used to lobby the Government against imposing regulations on fast-food advertising.