Australian medical researchers are calling for extra checks on gluten-free foods as some have been discovered to contain traces of gluten.

Food manufacturers are being urged to check their gluten-free products after tests found some aren't entirely free from gluten and may be dangerous for people with coeliac disease.

Melbourne researchers tested 256 food products labelled gluten-free and found small amounts of gluten in a small selection, meaning they didn't comply with national standards.

One gluten-free pasta contained 3mg of gluten, which the researchers said could potentially be harmful to people with coeliac disease.

While only seven products in total tested positive for traces of gluten, the researchers said the fact that three were produced in dedicated gluten-free factories meant manufacturers should check to see if their products could have been contaminated by ingredients from external suppliers.

"Our findings indicate that inadvertent gluten ingestion is more likely when dining out than when consuming manufactured gluten-free foods," the researchers wrote in a paper published in the Medical Journal of Australia on Monday.

"Nevertheless, more frequent gluten testing, feasible for many companies, would reduce the risk for people with coeliac disease."

An estimated one in 70 Australians has coeliac disease, according to Coeliac Australia which also estimates another four out of five people remain undiagnosed.

People with the condition have immune systems that react abnormally to gluten - the protein found in wheat, rye, barley and oats - and can suffer small bowel damage.

As a result, they are advised to steer clear of foods containing gluten.

As part of their study, the researchers from Royal Melbourne Hospital, Monash University and the Walter and Eliza Hall Institute of Medical Research carried out extra tests on fresh samples of gluten-free foods if initial results showed they contained gluten.

If a food product labelled gluten-free contains only a small amount of gluten, it's still in breach of the national standard for no detectable gluten.