North-West Tasmania has the highest per capita rate of obesity in the country, with high levels of type 2 diabetes and heart disease.

Rates in the North are similarly high, with Tasmania being the most obese state in Australia.

Tasmanian Antiobesity Surgery Centre doctor Stephen Wilkinson said government prevention campaigns had done nothing to solve the problem.

Health Minister Michelle O'Byrne said health prevention was a complex task that required multi-faceted support.

She said eight state government preventative health programs were in place.

``We will not solve this overnight _  it will take sustained effort and it will take a constant search for ways to do things better,'' Ms O'Byrne said.

``One element to the issue of .?th.?th. (obesity) is making the healthy choice the easy choice.'' 

Dr Wilkinson said he agreed with comments made last week by former national Preventative Health Taskforce member Professor Paul Zimmet  that the political response to obesity had failed.

``The campaigns have had zero impact _  the evidence is the still-increasing obesity rates, despite a number of expensive programs that have been put in place,'' Dr Wilkinson said.

He said obesity prevention should focus on children, and should adopt incentive-based strategies.

``They could be as radical as paying people to reduce their weight, or providing parents with financial incentives to get their kids to exercise,'' he said.

Diabetes Tasmania chief executive Caroline Wells said she did not believe financial incentives for weight loss would achieve long-term results.

Ms Wells said social marketing campaigns were important as part of the overall strategy, which should include updated legislative change.

``I agree with a tax on junk food,'' she said.

``Legislation should also prohibit all other forms of promotion of unhealthy food to children.''