Diabetes New Zealand forecasts there will be more than 407,000 people with Type 2 diabetes in 2022.
The organisation says the Government is continually under-estimating the prevalence of the disease.
It says the prevalence of diabetes in 14 years is 60% more than estimated by the Ministry of Health.
The organisation says there will be more than 407,000 people with Type 2 diabetes in 2022 and an increased investment of $60 million a year is needed to reduce long-term costs.
The ministry says better detection is responsible for the rise in cases.