More than 84,000 people in Northern Ireland will suffer from diabetes by 2015, according to health officials.
And obesity is one of the key factors behind the estimated 25% rise in cases, a report published by the Institute of Public Health in Ireland (IPH) claims.
In 2005, just over 67,000 adults in Northern Ireland and 141,000 in the Irish Republic were diagnosed with either type 1 or 2 diabetes.
But Dr Kevin Balanda, of IPH, forecasts that by 2015 about 84,200 people in Northern Ireland and 193,900 people in the Republic will be diabetic.
This is an increase of 17,000 adults in the province and more than 52,000 in the Republic over the 10-year period.
"The vast majority of this increase is for type 2 diabetes and it is clear to us from our research that an increase in obesity is the key driver of changes in the prevalence of type 2 diabetes in the adult population," he said.
The group is now calling for a system to be set up across the whole of Ireland to monitor rises in obesity cases and conduct research into how these are influenced.
Registers must also be set up to assess how many cases affect adults and children, and whether they are suffering from type 1 or type 2 diabetes, it added.