New Zealand's high rate of childhood obesity could be putting the viability of our health system in doubt.

11 percent of children are obese and 80 percent of children go on to become obese adults.

A study in today's New Zealand Medical Journal suggests there aren't enough services to prevent childhood obesity.

Christchurch laparoscopic surgeon Steven Kelly asserts the country needs to take the issue seriously, warning the issue will cost us far more down the track.

"Diabetes, which obviously is caused by obesity, is extremely expensive to treat," Kelly said.

"80 percent of children will become obese adults, so childhood obesity predicts the future health of the population."

Research has also found unregulated food marketing of high-fat foods has a powerful impact on children's diets.