A study by Otago University says New Zealand is on the verge of a diabetes epidemic, with one in five adults showing early signs of developing the disease.
Researchers analysed blood tests from more than 3000 people and found 7% of those over the age of 15 had diabetes and 18.6% showed early signs of the condition.
One of the researchers, Professor Jim Mann, said the number of people with pre-diabetes was a shock. "Never did I imagine, nor did any of my colleagues imagine, that there were as many as we found."
Dr Brandon Orr-Walker, a diabetes specialist at Counties Manakau District Health Board, said the health sector is already struggling with the numbers of diabetic people.
He said authorities need to take a proactive approach on promoting food and exercise to prevent type 2 diabetes.
Diabetes New Zealand president Chris Baty said the latest figures, from 2008, showed the health cost of type 2 diabetes was $600 million.
"Those are just the health costs, they don't take into account loss of productivity or any of those other things."
The Ministry of Health aims to increase the number of people getting heart and diabetes checks and hopes 90% of those at most risk of developing the illness, including Maori, Pacific and South Asians, will be checked by July 2014.
Its target is for 75% to be checked by July this year, but about half the country's district health boards have not reached 60% of those most at risk.
A ministry spokesperson said it is working with DHBs and Primary Health Organisations to lift performance on the health targets.