Health experts are calling for stricter regulations on packaged foods after finding many contain misleading fruit and vegetable claims.

Beware that fruit roll-up and approach that can of soup with caution.

Australian researchers have found packaged foods are routinely fudging fruit and vegetable claims on labels.

They're calling on the government to crack down on the practice by bringing the claims within the scope of the food standards code.

At present, there is no limit on fruit and vegetable claims because they refer to ingredients rather than specific nutrients.

The Cancer Council NSW and the University of Sydney say that has to change.

Their researchers spent days rifling though supermarket shelves and photographing the labels of about 760 juices, soups and snacks.

Of the roughly 50 per cent featuring a fruit or vegetable claim, one-third failed a basic nutrition test based on sugar, salt and fat levels.

Many were found to lack the vitamins, minerals and fibre of genuine fruit and vegetables, the researchers found.

One brand of fruit bar, which claims to have one serve of fruit a serve, was 18 grams - short of the 30 grams defined as a dried fruit serve.

Another product, a fruit juice "made with real-life raspberries", contained 13 per cent fruit juice and 14 teaspoons of sugar.

Co-author Clare Hughes, of Cancer Council NSW, said food companies were cashing in on the recommendation to eat two serves of fruit and five serves of vegetables.

"We don't want people to be relying on these products for their fruit and veg content," she said.

"Nothing beats the real thing."

She urged shoppers to ignore claims and interrogate the ingredient list instead.

AAP.