Europe's opposition to genetically modified crops is robbing the developing world of a chance to feed itself and could threaten food security, a leading African scientist warns.

Dr Felix M'mboyi of the Kenya-based African Biotechnology Stakeholders Forum has accused the European Union of indulging in "hypocrisy and arrogance" and called on development bodies within Europe to let African farmers make full use of GM crops to boost yields and feed a world population expected to reach 7 billion by the end of the year.

M'mboyi's emotive language comes in the run-up to a major food conference in London supported by the biotechnology industry. It follows signs that some African governments are softening their opposition to crops that are genetically engineered.

Last year Kenya passed a Biosafety Act allowing commercial cultivation of GM crops, becoming the fourth African country to explicitly legalise GM crops

However, opponents of GM food said the technology had failed to live up to its promises. GM could actually reduce food security by narrowing the variety of crops grown while making farmers more dependent on multinational companies such as Monsanto and Dupont, they said.

M'mboyi, a former agricultural adviser to the Kenyan government, will make the keynote speech at the Crop World Global conference at the end of this month. He said: "The affluent west has the luxury of choice in the type of technology they use to grow food crops, yet their influence and sensitivities are denying many in the developing world access to such technologies which could lead to a more plentiful supply of food.

"This kind of hypocrisy and arrogance comes with the luxury of a full stomach," he said.

Some GM crops have been tested on a small scale in Africa. But governments are reluctant to introduce them commercially because they fear export bans from EU markets. M'mboyi will tell the conference, organised by the British Crop Production Council, that GM should not be ruled out and should be part of the mix along with conventional and organic production.

GM crops are grown in 29 countries on 3.7bn acres of land. While the US is by far the largest producer, about 48% of the world's GM plants are grown in developing countries.

Last week 20 food and conservation groups in developing countries reported that genetic engineering had failed to increase the yield of any food crop – but had increased the use of chemicals and growth of superweeds.

Mike Childs, head of climate for Friends of the Earth, said: "He's plain wrong if he says the EU are dictating what Africa can and cannot do. There is a strong grassroots movement against GM in the developing world largely because, where GM crops have been introduced, they have overpromised and underperformed.

"The solution to feeding Africa doesn't start with GM technology and certainly not with the GM crops that are being peddled by the big multinational companies like Monsanto."

Duncan Green, head of research at Oxfam, said GM crops were not the answer to ending hunger. Some would tie farmers into buying seeds and pesticides from western suppliers and would threaten the tradition of seed swapping practised by 80% of African farmers. "When you talk to people in developing countries about how to increase yields, GM comes pretty low down the list," he said.