There are concerns many Australians are consuming risky levels of salt just by eating bread.

A study by The George Institute of Global Health has found two slices of the food staple can contain more than a third of the daily recommended salt intake.

The World Health Organisation recommends adults should consume less than 2,000 mg of sodium, or five grams of salt to reduce their risk of stroke and cardiovascular disease.

While sodium levels in breads have dropped over the past seven years, there are still too many products containing levels risky to health, says lead investigator and public health nutritionist Clare Farrand.

For example, she says, two slices of white sourdough contains 2.3 grams of salt even before any type of product like Vegemite is added.

"This just goes to show that people get far more salt than they actually need just by eating bread alone," Ms Farrand told AAP.

Researchers at The George Institute analysed 1439 bread products from 2010-2017.

Average sodium content of bread and bread rolls had reduced by 10 per cent from 456mg per 100g to 408mg/100g in that time.

Most, 81 per cent, met the voluntary sodium target of 400mg/100g set by the Australian Food and Health Dialogue (FHD) compared to 37 per cent in 2010.

However only two-thirds of all bread products sold in Australia had set sodium targets, said Ms Farrand.

Concerningly, the products that contained the most salt were often considered the "healthiest by families" such as rye bread and wraps.

On average, rye breads contained 20 per cent more sodium.

Just one slice of Schwob's Dark Rye contained more than double the amount of salt as a 45g serving of Kettles sea salt chips, according to the study.

Artisan baker Bowan Island's Wholemeal Sourdough also stood out for its high salt content.

The analysis showed it was almost three times saltier than the lowest option Bill's Certified Organic 100% Wholemeal Sourdough, which only contained 0.6g salt/100g.

Flat bread such as wraps, naan, roti and tortillas on average contained a third more salt than white bread.

Ms Farrand says the study clearly highlights a huge difference in salt content among breads and encourages people to read the labels before purchasing.

She has also called for government supported salt reduction targets across all foods.

"Limiting the amount of salt in our most consumed foods would not only save lives, it would also reduce the burden on the Australian health system," Ms Farrand said.