Researchers are calling for a ban on what they describe as manipulative junk-food advertising aimed at children, saying it is helping drive up child obesity rates.
The researchers at Otago University's Wellington campus reviewed scientific studies on television marketing techniques targeting children.
They found the methods - including free toys, gifts, discounts, competitions, promotional characters and celebrities - influence children's diets and make them ask for junk food more.
Lead researcher Gabrielle Jenkin said most families are familiar with the offer of free toys at McDonald's and the use of characters like Spiderman or Spongebob Squarepants to promote such foods.
Dr Jenkin said a ban on such marketing to children under 16 should be imposed, as it has been in Norway.