"The current rate at which the type 2 diabetes incidence is increasing is similar to the increase in the type 1 diabetes population, which is 3-5 per cent per year. So this is a slow and steady incidence increase."
The study found that from 1995 to 2015, the service treated 104 young people for with type 2 diabetes, giving an overall incidence of 1.5 per 100,000.
But that jumps to 3.6 per 100,000 for Pacific Island youth and 3.3 per 100,000 for Māori, compared with 1.4 per 100,000 in Asian/Middle Eastern children and almost no cases in Europeans (0.2 per 100,000).
Girls and children from poorer households were also over-represented.
Dr Jefferies is a paediatric endocrinologist at Starship Child Health and a Liggins Institute researcher.
At the Starship Paediatric Diabetes Service, which provides care for all newly diagnosed children and young people in the Auckland region, Jefferies has seen children as young as 10 present with type 2 diabetes.
"The ethnic differences are striking and are partly related to differences in the rates of overweight and obesity.
"Although, as the differences in weight problems between ethnic groups is smaller than the differences in type 2 diabetes rates, weight is not the whole picture."
Jefferies said there was also an increase in Asian youth that were not seen before – though this may reflect immigration patterns.
"Some families are shocked by the diagnosis – they don't see diabetes as a childhood disease".
He said if you pick it up early, you can manage it through diet, exercise and medication.
"Our findings are a reminder for parents, schools and healthcare professionals to keep an eye out for symptoms of diabetes in young people."
Type 1 diabetes, an auto-immune condition which cannot be prevented but can be managed through a healthy lifestyle, is about five times more common than type 2 diabetes in young people.
Symptoms of both types of diabetes include feeling tired and lacking energy; losing weight; feeling thirsty; going to the toilet often; waking at night to go to the toilet; wetting the bed when previously dry; and getting frequent infections, or infections that are hard to heal.