Research by health professionals shows the nutritional labels are not having much impact on New Zealanders' food choices.
The figures were presented at a symposium in Wellington yesterday looking at how New Zealand can tackle diet-related disease.
University of Auckland researchers looked at the way in which shoppers used Traffic Light Labels and Health Star Ratings on various food products and were surprised to find the labels made little difference to which foods were purchased.
The study's lead author, Professor Cliona Ni Mhurchu, said people who were interested in healthier choices used the labels more than the majority of survey participants, but overall none of the labels significantly changed what people bought.
There were other ways people could be encouraged to eat more healthily, including making healthier food available in different settings such as schools, workplaces and hospitals, she said.
"But what we also know is unhealthy food is readily available and heavily marketed so we really also need to be looking at marketing regulations."
Professor Ni Mhurchu said the government needed to become more involved in setting standards around how food was marketed, rather than leaving that to the Advertising Standards Authority.
"[Advertising is] not being monitored, [it's] not being evaluated, it's not the government setting the standard."
Ms Ni Mhurchu's colleague, Professor Boyd Swinburn, echoed her call for tighter regulation.
He was involved in a study which found over a quarter of less healthy food products carried nutritional claims. With breakfast cereals nearly two thirds of less healthy options carried such claims.
Professor Swinburn said it created a huge potential to mislead consumers.
"We found large numbers of unhealthy products contained nutrition claims and we wondered if they should be more closely regulated like the health claims now are.
"You can't put a health claim on unhealthy food, but should you be allowed to put a positive nutrition claim on a food that is fundamentally unhealthy?"
Mr Swinburn pointed to food product warnings used in Chile and Brazil, which he said could be very effective.
"It is a much more powerful stimulus when it has a stop sign on it which says, 'This is high in salt or high in sugar'.
"If we're not careful our whole health star rating system is going to get overtaken by a better one in another country."