Cancer Council Australia chief executive Professor Ian Olver said a worrying cycle was emerging, as overweight and obese children often became the next generation of overweight and obese adults who, in turn, had a ''significantly increased'' risk of developing cancer.

''Put these together and we're facing a potential spike in obesity-related cancers, including breast and bowel cancer, over the next few decades,'' Professor Olver warned before World Cancer Day tomorrow.

''So World Cancer Day should remind the Government that we must act now to reduce childhood overweight and obesity, and prevent thousands of premature cancer deaths in Australia.''

World Cancer Day is organised by the International Union Against Cancer and its theme for 2009 is to ''encourage an energy-balanced lifestyle''.

Professor Olver said the theme again highlighted the urgency for the Federal Government to adopt its own Preventative Health Taskforce's recommendations for a comprehensive national obesity strategy this year.

The taskforce, which involves some of the nation's leading experts in chronic disease prevention, is now in community consultation over its draft recommendations.

''The test will be the Government's willingness to implement the taskforce's recommendations, which will require tough decisions around food marketing, production and labelling, and building communities that support physical activity,'' Professor Olver said.

He also said the Government efforts to offset the global economic downturn should not overlook boosting spending on public health programs, to foster a healthier and more productive population in the longer term.

''Obesity cost Australia's health system $2billion last year and reduced productivity by $3.6billion,'' Professor Olver said.

''So investing in a strategy to reduce obesity ... would make good economic sense, while helping thousands of Australians to reduce their risk of cancer over the long term.'' AAP