Diabetes is attacking young people aged between 12 and 18, according to Diabetes New Zealand.
New estimates indicate 500 young people in the age group have Type 2 diabetes, the disease that was, only a few years ago, virtually unknown in people of that age.
"It used to be a disease that only affected adults over 45 years old, but not any more," Mike Smith, president of Diabetes New Zealand, said today.
Mr Smith said Diabetes Awareness Week, November 18-24, was a good time people to think about how they could play a part in reducing the impact the life-threatening disease was having on society.
"It's our own inaction that is allowing Type 2 diabetes to become an epidemic."
While Type 1 diabetes was also on the increase, it was the increased prevalence of Type 2 diabetes which was tied back to lifestyle choices.
The fact that it was often preventable made the Type 2 diabetes epidemic even more tragic, he said. It could often be delayed and possibly prevented by eating less and exercising more.
"Once one person in a family has `got diabetes', everyone has it, in effect," Mr Smith said.
"Those in the family who may not have the condition will certainly feel its effects, in the time spent caring for family members.
"In more advanced cases this means helping them come to terms with blindness, amputation and kidney failure."
Mr Smith said there were 180,000 New Zealanders diagnosed with all types of diabetes. There were also 80,000 immediately at risk, having a condition called pre-diabetes and another 800,000 overweight or obese people in New Zealand who were at longer term risk of developing Type 2 diabetes.
The emphasis in this year's Diabetes Awareness Week is on young people and families.