Thousands of children are being failed by health services across the country according to the Coeliac Society.
It also says that over 7,000 children are living with the condition without knowing.
Ahead of coeliac awareness week, the society is calling for an increased focus on diagnosis, particularly among children from poorer backgrounds.
Coeliac Society dietitian Sarah Keogh says it is a major problem.
"What we see with our members is that it takes quite a long time for adults- the average is about ten years- to be diagnosed coeliac from when they first start to get symptoms.
"With children it's often a little quicker, but either they're completely missed or even when we do see kids it could take a year or even two years for them to be diagnosed once they start having symptoms.
"So there's just this delay that's not being picked up as much as it needs to be."