There are currently 2.3m diabetics in the UK
Diabetes costs the NHS over £1m a day in NI, almost 10% of general NHS spending, a report has said.
The report published on Wednesday by Diabetes UK said that treating diabetes was one of the biggest challenges facing the NHS in NI.
Iain Foster, Diabetes UK Northern Ireland director, said: "Diabetes leads to heart disease, stroke, amputations, kidney failure and blindness.
"It causes more deaths than breast and prostate cancer combined," he said.
Peter Gibson, who has had diabetes since he was a toddler, said it was "one of the very few medical conditions that can affect from the top of your head to the tip of your toes".
"If you can look after your condition, the likelihood of complications that can affect potentially any part of your body can be held back and ultimately prevented."
Diabetes UK has launched the 'Silent Assassin' campaign to highlight that diabetes is a serious condition and to improve awareness of its devastating complications.
"Type 2 diabetes can remain undetected for 10 years or more before someone is diagnosed. It really is a silent assassin," said Mr Foster.
"More than 500,000 people have the condition but do not even know it and by the time they are diagnosed 50% of people are found to have started developing complications."
There are currently 2.3m people diagnosed with the condition in the UK and it is estimated that there will be more than four million people with diabetes, both diagnosed and undiagnosed, by 2025.