Britons are increasingly worried about genetically modified foods, a survey by consumer magazine Which? suggests.
Activists protested against "GM milk" earlier this year
Of the 1,000 people polled, 61% said they were concerned about the use of GM material in food production.
The poll also suggested more consumers are trying not to buy GM food, while fewer back GM crops in the UK.
Earlier this year, the government gave the go-ahead to the commercial growing of a variety of GM maize, but banned two more varieties of crops.
According to the poll, the number of people who are wary of GM foods and try to avoid them has gone up from 45% in 2002 to 58%.
"Consumers clearly don't want GM food and are hardening their stance against it," said the editor of Which?, Malcolm Coles.
"It's hardly surprising when questions still remain about the risks for health and the environment," he added.
He went on to say that the government had ignored the public's concerns for long enough and needed "to rethink its policy before going ahead with growing GM crops commercially".
Fewer people are happy with having GM crops in the UK - only one in four Britons compared to one in three two years ago.
Finally, the number of those satisfied with manufacturers removing GM ingredients from their products has gone up 5%, from 28% to 32%.
Products such as flour, oils and glucose syrups have to be labelled as do maize, soybeans, tomatoes and chicory, according to the Food Standards Agency.
However, products such as meat, milk and eggs from animals fed on GM feed do not need to be labelled, nor do cheese or bakery products produced with GM enzymes.
A Greenpeace spokesman said: "GM products in this country, such as maize, are almost exclusively found in cattle feed, and not products for human consumption.
"Using non-GM animal feed does not cost much more - for example, it would add 1p to a litre of milk, which supermarkets would be more than able to absorb. But they are not telling farmers to use non-GM feed, claiming the cost is too high.
"They have been good at getting GM ingredients out of food because of the public outcry, for example over GM tomato paste, but they have not been as good with animal feed."
Environmentalist group Friends of the Earth welcomed the Which? survey.
Clare Oxborrow, the group's GM campaigner, said: "Public opposition to GM food and crops is growing, yet the government is planning to allow widespread GM contamination of non-GM crops.
"The government must listen to the public and introduce tough new rules to keep our food, farming and environment GM-free."
In March this year, Environment Secretary Margaret Beckett gave the green light to cultivation of herbicide-tolerant maize for animal feed.
She rejected GM beet and oilseed rape, which had been recently tested in so-called farm-scale evaluations.
But environmental activists and farmers' groups this summer staged several protests at Sainsbury's depots and supermarkets.
They accuse the chain of producing and selling milk and dairy products from cows fed on imported GM feed.
But Sainsbury's replied there was "no evidence" that milk from animals fed on such crops contained any GM material.