A study of almost 3,000 people found those who consumed the most salt were almost twice as likely to develop diabetes.
And the risk rose almost four-fold for those genetically predisposed to the condition, according to the research.
Just under half a teaspoon (2.5g) extra a day increased the risk of type 2 diabetes, the form linked to obesity, by 65 percent.
Participants with the highest consumption – one-and-a-quarter teaspoons or more – were 72 percent more likely to develop it than those with the lowest.
The risk of developing LADA (Latent Autoimmune Diabetes in Adults), a form of type 1 diabetes, was even greater, increasing 82 per cent rise for each 2.5g consumed daily.
And it nearly quadrupled for those who ate lots of salt and carried specific gene mutations.
Dr Bahareh Rasouli, of The Institute of Environmental Medicine at the Karolinska Institute in Sweden, said: “We confirm an association between sodium intake and type 2 diabetes.
“High sodium intake may be a risk factor for LADA, especially in carriers of high risk HLA genotypes.”
Unlike type one diabetes, which usually is diagnosed in children, LADA is slow developing and often makes its first appearance in adulthood.
Variants in HLA (human leucocyte antigen) genes have been shown to increase the risk of developing diabetes.
Dr Rasouli added: “These findings may have important implications in the primary prevention of diabetes with adult onset.”
There are currently around 4.5 million people in the UK who now have diabetes, with 90 per cent of cases thought to be type 2. But the condition can be very significantly improved through a simple, healthy diet.
The NHS advises adults should eat no more than 6g of salt a day, about a teaspoon, and children even less.
The research, presented at the European Association for the Study of Diabetes in Portugal, is the strongest yet to link diabetes with high salt consumption, which is known to be bad for health by increasing blood pressure.
Dr Rasouli and colleagues, whose findings are also published in the journal Diabetologia, believe sodium – which makes up 40 per cent of salt – makes the body resistant to the glucose controlling hormone insulin.
So for every 2.5g of salt consumed, 1g is sodium. Previous research has suggested too much salt may increase the risk of developing type 2 diabetes, possibly through a direct effect on insulin resistance, and by causing high blood pressure and obesity.
Dr Rasouli’s team set out to shed more light on the association by using data from a Swedish population-based study of 355 patients with LADA and 1,136 with type 2 diabetes and comparing them to 1,379 healthy controls.
Dietary intake was recorded using a food questionnaire and used to calculate the daily consumption of calories, nutrients and sodium.
The influence of genetics on diabetes risk was also considered, with patients being divided into ‘high risk or ‘other’ according to their HLA genotype.
The team also took into account risk factors including age, sex, BMI, smoking, physical activity, family history of diabetes, alcohol and total energy and potassium intake.