Only a quarter of shoppers in Wales are happy to buy genetically-modified food - and more than a third want it banned altogether.
Protesters have attacked fields containing GM crops
The Welsh Consumer Council (WCC) is due to reveal the full findings of its latest survey on Thursday at the National Eisteddfod in Meifod, mid Wales.
The survey of more than 1,000 consumers - made public a week after Prince Charles called for a GM-free Wales - illustrates that there is still public confusion over the GM debate.
The WCC survey - To Eat or Not to Eat - found that 74% of all consumers in Wales want food containing genetically-modified ingredients to be clearly labelled.
And, despite a quarter of those surveyed being happy to buy foods containing GM, more than half said they were worried about the environmental impact of growing GM crops in the UK.
74% want GM ingredients labelled
38% say ban GM foods
51% worry about the environmental impact of growing GM crops
The Welsh Consumer Council says the results send a strong message to the UK and Welsh Assembly Government that the case for GM is not yet proven.
One fact which emerged from the survey was that, despite a public consultation on the subject, many people were still confused about the meaning of genetic modification.
Welsh Consumer Council Chair Vivienne Sugar said the report sent a clear message to politicians - that Wales was not ready for GM foods.
"The case for GM is not proven," she said.
"Where GM material is for sale, consumers demand the right to choose, and many remain deeply worried about the impact on the environment of growing GM crops in Wales or the UK."
Mrs Sugar said the voices of the ordinary people in Wales must be heard.
"There is a perception that the interests of big business
are driving GM developments," she added.
"But in matters of food and health, consumers must be able to have confidence that government and government agencies are championing their interests.
"In the GM debate, there is a perception that too much emphasis is being given to commercial benefit rather than reducing consumer and environmental risk."