More than 1.1 million adults are now obese, according to the Ministry of Health's 2012/13 health survey. The adult obesity rate has risen to 31 per cent - up from 29 per cent a year ago and 27 per cent in 2006-07.
Obesity rates are highest in Pacific adults; 68 per cent are obese.
Adults living in the most-deprived areas are 1.5 times as likely to be obese as those in the least-deprived areas.
Eleven per cent of children aged 2-14 years are obese; that's about 85,000 youngsters. The childhood obesity rate is similar to last year's, but has increased significantly since 2006-07.
Jim Mann, professor of human nutrition and medicine at Otago University, said the new figures were depressing rather than surprising.
Government action, including attempts to increase physical activity, fell well short of what was needed, Professor Mann said.
An over-arching strategy to deal with the obesity problem was needed, including meaningful school programmes, curbs on the advertising of unhealthy foods, and an easy-to-understand food-labelling system.
"Food is the big factor. There is still huge promotion of junk foods and not a lot to counter it ... We have to be taking the lead - signal that we have a problem ... There's not even healthy food in many hospitals."
Obesity increases a person's risk of developing type 2 diabetes, high blood pressure and heart disease. Professor Mann said dealing with the complications of those conditions, such as limb amputations, blindness and renal dialysis, had huge consequences for the health system.
The Government focus for new nutrition programmes has been on mothers and babies. It is also spending more on screening for diabetes and cardiovascular disease, and on providing more "green prescriptions", in which GPs and nurses encourage patients to get more exercise and improve their diet. Some health advocates have called for more radical action, including taxing sugary drinks and fatty foods.
However, Mr Ryall said the Government's preference was to provide information and support "rather than nanny-state regulation".
"These are international trends. Every developed country is struggling with this challenge.
"The Government is investing around $60 million a year across a range of programmes from Kiwisport in schools to green prescriptions to fruit in schools. We are also currently considering a highly successful community-based programme from Victoria which supports individuals, families and communities to make healthy change."
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Body mass index (BMI) is a commonly used measure to classify underweight, overweight and obesity in children and adults. BMI is calculated by dividing weight in kilograms by height in metres squared (kg/m2). For an adult aged 18 and over, a BMI score of 30 or more is classified as obese. Overweight is between the range of 25-29.99, and normal 18.5-24.99. A BMI lower than 18.5 is considered underweight. BMI provides only a crude measure of body fatness in individuals.
Source: Ministry of Health
