A study has detected potentially harmful levels of gluten in foods sold and served as 'gluten-free' across Melbourne.

People with coeliac disease have been warned many eateries are still serving meals containing harmful levels of gluten despite being advertised as 'gluten-free'.

Nearly one in 10 gluten-free meals sold in Melbourne were found to contain gluten, according to a study published in the Medical Journal of Australia on Monday.

Some meals contained such high levels of gluten that they would be considered unsafe for people with coeliac disease by food safety authorities.

The research has led to calls by Coeliac Australia for improved education and awareness of restaurant and cafe food staff.

"Gluten-free remains one of the top dietary requests and we urge all food businesses to treat gluten-free requests seriously," said Coeliac Australia President Michael Bell.

Treatment of coeliac disease includes a lifelong strictly gluten-free diet; exposure to even tiny amounts of gluten can damage the person's small intestine.

Gluten can be found in grains such as wheat, rye, barley and oats.

Researchers, led by gastroenterologist Dr Jason Tye-Din at the Walter and Eliza Hall Institute of Medical Research and Royal Melbourne Hospital, analysed 158 'gluten-free' dishes from 127 randomly selected food businesses in Melbourne.

They found nine per cent, or 14, contained detectable gluten and were therefore not compliant with the Food Standards Australia New Zealand (FSANZ) definition of gluten-free.

Of these non-compliant dishes, nine contained more than 20 parts per million (ppm) gluten, the upper threshold for safe gluten intake in Europe and the United States.

"One business provided wheat-based foods (> 80 ppm gluten) despite a gluten-free meal being requested, reflecting the lack of understanding reported by many people with coeliac disease," the authors wrote.

An additional survey of food staff found only 10 per cent had 'good' knowledge of FSANZ guidelines.

They were also "particularly ignorant" about spelt, which contains gluten.

The good news was that non-compliance rates had improved since earlier audits in 2014 and 2015, most likely due to greater scrutiny by environmental health officers and education.

"Indeed, four of five venues of one burger chain were non-compliant in 2014, but all were fully-compliant in 2015 and 2016," the authors said.

"The increasing community demand for gluten-free food may also be a driver of increased awareness among food service staff of the importance of avoiding gluten contamination."