The multinational weight-loss group will make its case at an obesity summit in Canberra next week, backed by what it says is a growing body of international evidence about the success of its approach, which is a mix of education on diet and exercise, regular monitoring and peer support.

Weight Watchers International chief scientific officer Karen Miller-Kovach pointed to a study - funded by Weight Watchers through a grant to the UK Medical Research Council and published last year in the Lancet - which found overweight and obese adults in Australia, Germany and the UK who were given a 12-month Weight Watchers membership lost twice as much weight as another group who were treated by a general practitioner. A study published in the International Journal of Obesity this year found Weight Watchers programs were more cost-effective than GP treatment.

''It's time for governments to move beyond the problem of obesity to taking action to solve it,'' Ms Miller-Kovach said.

''There is a growing pool of evidence that there are solutions that are available today that are affordable, that they are effective and they are scalable.''

Ms Miller-Kovach said Weight Watchers succeeded where sometimes GP treatment failed because frequent contact and accountability was needed as well as information about diet and exercise.

''Just because you know what you're supposed to do, doesn't mean you do it. There is a real need for behaviour change,'' she said.

Ms Miller-Kovach said weekly contact was needed but it was too expensive for healthcare professionals to provide this level of support. ''Healthcare time is so expensive. Just checking in with your doctor once a month is not enough, and it doesn't need to be the doctor.''

She nominated the United Kingdom, where GPs in some areas receive government funding to refer people for commercial weight-loss programs, as a model Australia could learn from.

Weight Watchers Australasia managing director Joseph Saad said the weight-loss industry, with the support of the Australian General Practice Network, had put a proposal to both major parties in 2007 for a program which would provide subsidised 12-week weight-loss programs to overweight people referred by their GP. The proposal was costed at $115 million over three years. The cost of each program would be $202, with $30 paid by the patient and the rest by the taxpayer.

''Our view is that a totally new approach needs to be looked at, and commercial organisations need to be allowed to get in the game,'' Mr Saad said.

Nutritionist Rosemary Stanton said the Weight Watchers program was quite sound, but she had concerns about public subsidies going to a commercial organisation whose aim was to generate profits.

Boyd Swinburn, a professor of population health at Deakin University and director of the World Health Organisation Collaborating Centre for Obesity Prevention said the idea was worth considering because there was a reasonable evidence base for such programs. But he questioned how affordable such an approach would be, given the numbers of people who were overweight or obese.

Obesity Policy Coalition spokesman Craig Sinclair said while weight-loss initiatives were always welcome, the government needed to take a broader approach, including tackling environmental factors which drove obesity such as junk food marketing, food labelling and the cost of fresh food.