The World Health Organisation was yesterday accused of burying a report recommending that curbs on junk food advertising be incorporated into global food standards.

Activists say hiding the report, which also calls for tough limits on sugar, salt and fat, comes after pressure from the food industry and its US backers.

The report, commissioned from outside consultants, was completed in the summer but has not seen the light of day. It recommends that the Codex Alimentarius - the global food standards code set up by the WHO and Food and Agriculture Organisation - should contain not just safety and quality information, but nutritional guidance as well.

The code is not binding on governments, but is influential with those who set their own standards, like the UK, and has particular significance for developing countries that do not.

The report, of which the Guardian has a copy, recommends sweeping changes to the code as part of the fight against the global obesity epidemic. It was commissioned during the tussle over the WHO's global strategy on diet, physical activity and health, which proposed limits on the consumption of fats, sugars and salt and was fiercely opposed by some in the food industry. The strategy was finally passed by the World Health Assembly in May.

Officials at the WHO say the report was not intended to be published. But Bruce Silverglade, of the US-based Centre for Science in the Public Interest, believes that the report, Food Standardisation to Support the Reduction of Chronic Diseases, may have been buried as part of a deal to get the strategy approved by those who did not want limits on fat, sugar and salt in the diet.

"It appears that its suppression may have been a quid pro quo for the support of the US government and others who had initially opposed adoption of the WHO's anti-obesity strategy," he said. "The document is a key element in the implementation of the WHO's global strategy - it gives it teeth. The food industry would not want to see this document come to light. Developing countries are directly influenced [by the code] and they provide the food industry with its biggest emerging markets."

The report says that the Codex Alimentarius Commission should support the global strategy in the fight against obesity-related diseases by formulating guidelines on the labelling, presentation and promotion of food to the consumer. "These guidelines and codes of practices should address the promotion of foods directed at children, food promotion activities in schools, activities of the food industry, the catering organisations and the retail sector," it says.

It says that the Codex can and should recommend foods with low energy density - such as unsaturated rather than saturated fats and the substitution of sugars by non-nutritive sweeteners. It also suggests that limits be imposed on salt.

The global strategy that was agreed in May calls on governments to take measures to curb unhealthy eating, promote exercise and look at food labelling and advertising. But governments like the US which have a strong sugar industry maintained that they should not have to restrict trade in the process and that they could set their own national nutritional guidelines.

Robert Beaglehole, head of the department of chronic disease prevention and health promotion at the WHO, said that negotiating changes to the Codex would be a long and difficult process. "It is not a huge priority." He said there was no reason why the report had not been published. "There have been so many things going on. I don't think there's a conspiracy," he said.