Writing in the BMJ, they say the new target will result in tens of thousands of people having to take more medication as GPs take a tighter control of blood glucose in patients with diabetes.
The new target, agreed between GPs and government officials, would help reduce the risk of heart disease in diabetics, according to the Department of Health.
The Quality and Outcomes Framework will start in April, and will pay GPs for areas of patient care. It will mean that doctors will have to cut blood glucose levels in half of their type 2 diabetic patients to below 7%.
If this is achieved, GP practices will get around£3,000 - around the amount they currently get paid for reaching a blood glucose target of 7.5%.