World governments focus too much on fighting terrorism while obesity and other "lifestyle diseases" are killing millions more people, an international conference recently heard.

Overcoming deadly factors such as poor diet, smoking and a lack of exercise should take top priority in the fight against a growing epidemic of preventable chronic disease, legal and health experts said.

Global terrorism was a real threat but posed far less risk than obesity, diabetes and smoking-related illnesses, prominent US professor of health law Lawrence Gostin said at the Oxford Health Alliance Summit here.

"Ever since September 11, we've been lurching from one crisis to the next, which has really frightened the public," Gostin told AFP later.

"While we've been focusing so much attention on that, we've had this silent epidemic of obesity that's killing millions of people around the world, and we're devoting very little attention to it and a negligible amount of money."

The fifth annual conference of the Oxford Health Alliance -- co-founded by Oxford University -- has brought together world experts from academia, government, business, law, economics and urban planning to promote change.

An estimated 388 million people will die from chronic disease worldwide over the next 10 years, according to World Health Organisation figures quoted by the alliance.

"There's a political paralysis in dealing with the issue," said Gostin, an adviser to the US government and a professor at Georgetown and Johns Hopkins universities.

He noted that prevention of obesity and its effects had hardly rated a mention in the current campaign for the US presidency.

"Yet the human costs are frightening when we consider that obesity could shorten the average lifespan of an entire generation, resulting in the first reversal in life expectancy since data collecting began in 1900," he said.

Like terrorism, some passing health threats get major government attention and media coverage, while heart and lung disease, diabetes and cancer account for 60 percent of the world's deaths, the meeting was told.

"It is true that new and re-emerging health threats such as SARS, avian flu, HIV/AIDS, terrorism, bioterrorism and climate change are dramatic and emotive," said Stig Pramming, the Oxford group's executive director.

"However, it is preventable chronic disease that will send health systems and economies to the wall."

The conference is due to end Wednesday with a "Sydney Resolution" calling on governments and big business among others to take action to avert millions of premature deaths due to chronic disease.

"The way we live now is making us sick, it's making our planet sick and it's not sustainable," said Asia-Pacific co-director Ruth Colagiuri.

The Sydney resolution focuses on four key areas, including the need to make towns and cities healthier places in which to live by urban design which promotes walking and cycling and reduces carbon emissions from motor vehicles.

Insufficient physical exercise is a risk factor in many chronic diseases and is estimated to cause 1.9 million deaths worldwide each year, said Tony Capon, professor of health studies at Australia's Macquarie University.

"We need to build the physical activity back into our lives and it's not simply about bike paths, it's about developing an urban habitat that enables people to live healthy lives: ensuring that people can meet most of their daily needs within walking and cycling distance of where they live," he said.

The resolution also calls for a reduction in sugar, fat and salt content in food, making fresh food affordable and available and increasing global efforts to stop people smoking.