Prof Merriman, of the School of Medical Sciences in Dunedin, said sugary supermarket deals such as 50 peanut slabs for $40 at Countdown yesterday or three litres of soft drink for $1 at New World during Orientation Week encouraged poorer diets and went against the Government's $40 million Healthy Families NZ anti-obesity initiative.
From October, the health initiative would roll out in Invercargill, East Cape, the Far North District, Lower Hutt, Rotorua, Whanganui, Manukau, Manurewa-Papakura, Spreydon-Heathcote and Waitakere.
In each community, health promotion staff would work with schools, early childhood education centres, workplaces and sport clubs to encourage people to make healthy lifestyle choices.
Prof Merriman said the Government was not doing enough to fight the obesity crisis in New Zealand.
''The Government has clearly indicated it shows no interest in intervening in the free market. Supermarkets are definitely the worst offenders, in having such cheap food laden with sugar and very little nutrient ... How does he [Health Minister Tony Ryall] honestly think that the campaign is ever going to work?''
The obesity issue was complex but the Government should remove GST from fruit and vegetables and tax food with added sugar.
''The more sugar a food has in it, the more expensive it should be.''
The tax would apply only to added sugar and not natural sugar, he said.
The Government and free market were to blame rather than the consumers.
''People are being encouraged to buy good deals and the Government says that it is implicitly OK because it is a free market. Can you blame people? I don't.''
Mr Ryall said the Government had no plan to remove GST from fruit and vegetables or tax food with added sugar.
''A tax on food with sugar will make all new Zealanders pay to influence the decision of some. Such a tax would push up the cost of a whole range of staple products like honey and jam.''
When Mr Ryall was asked if he would like to change his sugary product list because honey had no added sugar, just natural sugar, and would be exempt from Prof Merriman's proposed tax, Mr Ryall said he stood by his comment.
The ODT contacted supermarket operators yesterday and asked if the comments about supermarkets being the worst offenders for selling cheap sugary food with little nutrient value was fair.
Foodstuffs New Zealand spokeswoman said its stores, including Pak'n Save, New World and Four Square, offered a mix of products on special to meet its customers' needs, including a mix of fresh and packaged goods, frozen foods and beauty products.
A Countdown spokeswoman said it reduced prices across the store and not just on popular items such as chocolate and chips.
''We're also working with our own brand suppliers to introduce the new health star rating on our own products.''
