Food giants are facing a clampdown on internet marketing targeting children under new proposals from a Dublin senator.
Fine Gael senator Catherine Noone has called for "loopholes" around how sugary and fatty foods are advertised to children to be closed.
One in four Irish children are obese and research shows that obese children are likely to become obese adults.
Food companies already face rules around marketing junk food to children on radio and television, but digital marketing has yet to be tackled in a comprehensive way.
Ms Noone, who is to contend for a Dail seat in Dublin Bay North, has called for action to be taken to curb online marketing in the same way radio and TV adverts are policed.
Under strict rules, food companies are not allowed to advertise during children's programming. In addition, only one in four adverts on radio or TV may be for high sugary and fatty foods on any one day.
The lack of regulation about online marketing "allows junk food and high-sugar beverage companies to target children as they see fit", Ms Noone said.
"This kind of marketing is much more effective than the traditional television advertisements. Companies can use data to deliver personalised, targeted adverts to young internet users," she added.
"The amount of children accessing the internet continues to rise and while these loopholes remain open, they will be exposed to targeted marketing.
"Parents have a right and expectation that their children should be allowed to access the internet without being targeted by companies promoting health-damaging products.
"We have recognised this problem through traditional forms of media; we must now bring our regulations up to date with our changing society by introducing similar restriction to online activity."
The Irish Heart Foundation has also called for a digital marketing crackdown, following a report which examined the tactics used by companies to target young people.
It found that children and young people are targeted by companies who can use social media to interact with them as if they were friends.
The charity has also backed calls for celebrities and influencers to be banned from promoting unhealthy food and drinks, in the same way they are banned from promoting alcohol.
Previously, the foundation's head of advocacy Chris Macey told a Dail committee that food companies have been employing the same tactics seen during the presidential election in the US to peddle junk food to children for years.
"Junk food marketing involves the world's best marketing brains in the biggest agencies relentlessly targeting children, who we know are way more susceptible to advertising, every single day," he said.