LONDON - A group of public health organisations said on Friday they were concerned that industries selling fatty foods, alcohol and cigarettes could hijack a United Nations meeting on how to tackle chronic disease in order to protect their own interests.

Chronic or non-communicable diseases (NCDs) like cancer, heart disease and diabetes kill 36 million people a year, and health groups say the food, drinks and tobacco industries contribute significantly to that toll.

In a letter to The Lancet medical journal, more than 140 international health organisations and campaign groups said the United Nations should ensure industry lobby groups are not able to manipulate the Sept. 19-20 meeting and its outcomes.

"There are clear conflicts for the corporations that contribute to and profit from the sales of alcoholic beverages, foods with high fat, salt, and sugar contents, and tobacco products -- all of which are important causes of NCDs," they wrote.

"Failure to address these concerns will undermine the development of competent policy ... and the confidence the global community and the public at large have in the UN's and WHO's ability to govern and advance public health."

The high-level U.N. meeting in New York aims to draw up international action plans to tackle growing levels of death and illness from NCDs such as cardiovascular disease, diabetes, respiratory diseases and cancer -- costly conditions that are often linked to diet, lifestyle habits and exercise.

According to the World Health Organisation (WHO), the global epidemic of NCDs is expected to accelerate, so that by 2030 the number of deaths from NCDs could reach 52 million a year.

While they are often thought of as diseases of the rich world, NCDs disproportionately affect people in poorer nations. More than 80 percent of NCD deaths are among people living in low and middle income countries.

A bit like climate change, preventing and treating NCDs requires wealthy nations and multinational firms to take a near-term financial hit to help prevent poor nations being overwhelmed in the future.

But fears are growing that with consumer industries lobbying hard and little political appetite for major financial commitments in economic hard times, the meeting may not produce the targets and action plans many public health organisations had hoped for.

The groups writing in The Lancet, including the UK National Heart Forum, World Cancer Research Fund International and the U.S. Center for Science in the Public Interest, said they were concerned about the impact of big business on public policy making.

If key conflicts of interest are not addressed, they warned "policies and recommendations will invariably be weakened to suit the interests of the powerful corporation."

"As a consequence, the public's health, workforce productivity, and the economy will be undermined by prioritising the interests of the food and beverage industries, as well as the pharmaceutical, technology, and treatment companies, over the public good," they said.