Health Minister Jonathan Coleman has been working on a major national obesity programme. The Prime Minister announced this would be a Government priority shortly after the 2014 election.

The Government is preparing to make a major announcement in the fight against obesity, as it looks to reverse a trend of expanding waistlines and the burden of disease that goes with it.

In the next few weeks it's expected the Government will announce a major package of reform, that could include changes in schools, primary health and a major public campaign targeted at children and parents.

It's believed this could include changes to how physical education is run in schools, with both Health Minister Jonathan Coleman and Education Minister Hekia Parata understood to be in discussions.

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And it was likely the programme would see health officials undertake intensive work with certain schools deemed to have issues around promoting healthy eating and exercise.

It's expected the national package to be announced will not involve any regulatory changes around sugar content and advertising, or taxes on unhealthy foods or drinks.

According to the most recent New Zealand Health Survey, 1.2 million New Zealanders are obese. That is three in every 10 adults and one in nine children.

The rates are worse in poorer areas, where on average two-thirds of adults and one-third of children are classed as overweight, and they vary among ethnicities; increasing among both Maori and Pasifika populations.

Obesity threatens to place a huge financial burden on an already-strained public health system, as it leads to chronic illness like type 2 diabetes and heart disease.

It's been nearly a year since Prime Minister John Key announced his cabinet, for the first time putting together the health and sports portfolios under Coleman.

Key said at the time that tackling obesity would be a major priority for the Government.

Official documents show the Ministry of Health has completed a major stocktake of programmes under both portfolios.

More than $82 million is currently spent across 76 projects.

A number of those projects are expected to be either merged, revamped or culled as the Government looks to develop a plan to reverse the trend that has seen New Zealand register as the third fattest country in the OECD.

"It will include interventions intended to influence the wider environment as well as targeted to those who are already overweight or obese," official advice says.

"Interventions will need to include a mix of both bottom-up community-led initiatives (such as through Healthy Families NZ), and top-down national initiatives (such as advertising codes of practice and national guidelines)."

But it's not known whether the addition of a national health target will be put in place to measure outcomes of the obesity programme.

Healthy Families NZ is a community programme partially rolled out by the Government.

It is based on a similar, much vaunted programme in Victoria, Australia. Children in Colac, southwest of Melbourne, were on average 1kg lighter than those in neighbouring towns. Their waists were on average 3cm smaller and they could also run faster and had lower body mass index scores.