Britain would be acting immorally if it did not make GM crop technologies available to poor countries, Owen Paterson told international crop scientists in a major speech that was dismissed by his opponents as "agribusiness propaganda" but was welcomed by scientists as "overdue".

"The problems we face in feeding ourselves in 40 years' time are very real and something we have to prepare for right now. At this very moment there are 1 billion people on this planet who are chronically hungry. Are we really going to look them in the eye and say 'We have the proven technology to help, but the issue's just too difficult to deal with, it's just too controversial?," he said at Rothamsted crop research station in Hertfordshire.

"It won't be long until the population moves from 7 to 9 billion and we'll have even fewer resources to feed them. It is our duty to explore technologies like GM because they may hold the answers to the very serious challenges ahead," he said.

Paterson argued that GM crops could fortify food with vitamins and prevent blindness and death. "[GM] is about making crops durable enough to survive sustained drought. It's about developing new medicines. It's about feeding families in some of the poorest parts of the world. We cannot expect to feed tomorrow's population with yesterday's agriculture. We have to use every tool at our disposal."

He also said that the crops would save forests being felled and would dramatically benefit the environment. "If we use cultivated land more efficiently, we could free up space for biodiversity, nature and wilderness. Research undertaken by a team at Rockefeller University has found that over the course of the next 50 years new technology, combined with improved agricultural practices across the world, could release an area 2.5 times the size of France from cultivation."

But some environment and development groups dismissed his arguments as simplistic. "Paterson's GM dream will make it harder to feed the world. The government constantly claim that GM crops are just 'one tool in the toolbox' for the future of farming. In fact GM is the cuckoo in the nest. It drives out and destroys the systems that international scientists agree we need to feed the world. We need farming that helps poorer African and Asian farmers produce food, not farming that helps [GM companies] Bayer, Syngenta and Monsanto produce profits," said Peter Melchett, policy director of the Soil Associaiton, the organisation that represents organic agriculture.

"Paterson remains blinkered by the unfulfilled promises of GM crops. GM technologies have consistently under-performed, despite claims from the biotech industry. Where GM crops have been planted they are locking farmers into buying inputs and costly seed, while encouraging resistant weeds and insects and not delivering the increased yields as promised. The main causes of hunger – poverty and global inequalities in the distribution of food cannot be resolved by GM crops," said Mike Childs of Freinds of the earth.

"Paterson appears to [ignore] any science not peddled by big corporations. Only industry-funded research shows any benefits from GM crops, which do not increase yields and are having harmful effects on the environment in North and South America," said Helen Wallace, director of GeneWatch UK.

But the minister's call for GM crops to be widely grown in poor countries was backed strongly by some scientists. Sir Gordon Conway, former chief scientist at the department for international development, said: "It is a brave speech although long overdue. Millions of smallholders in the developing countries — in China, India, Africa and Latin America — are already significantly benefiting from growing GM crops".

Sir Mark Walport, the government's chief scientific adviser, said: "We need to use the whole range of agricultural technologies to ensure that we have the food to feed a burgeoning global population in challenging climatic and environmental conditions. Genetic modification is an important tool and is widely used in agriculture."

Greenpeace responded that the UK government was ignoring major advances made in conventional crop-breeding techniques which used the latest scientific techniques. "Paterson should be asking what works rather than blindly following agribusiness propaganda. The international consortium of research centres .... has used non-GM techniques to produce dozens of varieties of drought-tolerant maize, increasing African farmers' yields by 20 to 30%," said Greenpeace UK's chief scientist Doug Parr. "A host of other successes include blight-resistant potatoes and crops enriched with vitamin A, iron and other essential nutrients."

Paterson said that he would explore ways to overcome barriers to growing the crops in Europe. "We need evidence-based regulation and decision-making in the EU. Consumers need accurate information in order to make informed choices. The market should then decide if a GM product is viable. Farmers are also consumers but right now that market is not functioning and they are being denied choice. That's why I want to explore ways of getting the EU system working, as this will encourage further investment and innovation."