Which? has launched the campaign following letters sent out to 11 UK companies that licence cartoon characters and five food companies that use their own cartoon characters on foods, in which they asked whether they have specific policies on how characters can be used to promote foods to children.
"Overall most companies that use, own and license the cartoons used on foods high in fat, sugar and salt are still failing to acknowledge the need for effective action," said Which?
But the Food and Drink Federation (FDF) has responded with director of communications Julian Hunt calling the report "bizarre, given that the UK already has some of the strictest regulations in the world when it comes to advertising and promoting food and drink products to children".
He claims industry is fully complying with these rules.
"We are disappointed with the timing of this report because we are working with stakeholders, including Which?, via the Department of Health's Advertising and Promotion Forum to look at areas such as packaging," said Hunt.
For its part Which? said: "Many companies claim to have responsible marketing policies on how they promote their products to children.
However, our 'Food Fables' report exposed the gap between industry rhetoric and reality."
Conflict between Which?
and the FDF is nothing new, and the new campaign indicates that debate over advertising and its potential role in obesity and unhealthy eating practices is set to rumble on.
The campaign, which aims to get parents and other consumers involved through an online 'wall of shame' where they can post details of offending ads, comes less than three months after the introduction of the first wave of curbs on television advertising of high fat, sugar and salt (HFSS ) products around programming aimed at children.
But Which? says: "There are no controls in place to cover food packaging or company websites."
According to the group, this leaves the way open for 'child-catchers' like competitions, viral marketing and games.
The Committee of Advertising Practice has a code covering food marketing in areas such as magazine, email, poster, cinema and video advertisements, under which it says marketing should not condone or encourage poor nutritional habits or an unhealthy lifestyle in children.
Although Which? recognises this, it says that in practice older children will be still exposed to food companies' own branded characters, like the Nesquick Bunny and Coco the Monkey.
Which? used the controversial Food Standards Agency nutrient profiling scheme as the benchmark - and that in itself has come in for criticism by the industry as being 'unscientific'. Which?
did concede that not all the companies were 'baddies', however.
The BBC, Co-op, Disney and Warner Brothers were amongst those licensors said to have "responsible policies" in place.
On the food industry side Kelloggs and McDonalds are flagged as companies that have "made some steps in the right direction, but their policies are limited in scope".
A previous flashpoint of debate between Which? and the FDF has revolved around salt in food products.