An Otago University study has found nearly two-thirds of adults are eating more salt than is recommended.
A high salt intake can lead to high blood pressure, heart disease, strokes and kidney disease.
The results from the New Zealand Adult Nutrition survey were presented in Queenstown on Friday, showing the average sodium intake for adults is about 3500 micrograms, or about nine grams per day.
The recommended amount of sodium is 2300 micrograms per day.
The survey found about threequarters of the salt adults consume is from processed food.
Researcher Rachael McLean says it is not enough to limit table salt in meals, because most of the salt in people's diets is from processed foods.
Dr McLean told Checkpoint the salt is hidden in foods that people wouldn't expect to contain it and that may not necessarily taste over-salty, such as breakfast cereals, cakes and muffins.
She says processed foods should be reformulated to contain less salt and the Government should bring in guidelines.
But Dave Monro from the Heart Foundation says the food industry is doing well at lowering salt levels in processed foods on a voluntary basis.
The research found younger people and men aged between 19 and 44 consume on average almost double the recommended maximum level of salt.