Public health researchers say the Advertising Standards Authority is failing to prevent junk food manufacturers from targeting children in their marketing.
The Otago University researchers say the industry self-regulating body should be replaced by Government regulation.
Lead researcher Louise Thornley says the authority is not implementing the codes for advertising to children and advertising food, which she says is contributing to childhood obesity.
"What our research found was that there are problems with the system of self regulation, which isn't working here.
"More and more countries now are moving towards having Government regulation."
Authority chairman Rick Osborne says the organisation is about to introduce a new code which will place more responsibility on the manufacturers and advertisers of food. He says the code will allay the researchers' concerns.