In Ireland, 61% of adults and 22% of 5- to 12-year-olds are overweight or obese, and obesity-related health problems are costing the economy on the island of Ireland €1.6bn a year.

The tax would target any sweet and sugary non-essential foods that have no nutritional value and would be seen by experts as a “wake-up call” to people consuming too many of these foods. Doctors also believe the tax would “start a conversation” about nutrition, healthy diet, and sugar-laden foods.

Efforts were made to introduce a “sugar tax” on soft drinks before the 2012 budget. However, these were thwarted when the soft drinks industry claimed the sector was being unfairly targeted.

The Department of Health’s special advisory group on obesity is to present a range of incentives to encourage healthy eating and disincentives against eating sugar-dense, nutritionally empty foods to Mr O’Reilly in the coming months.

The group is considering recommending a health quota in vending machines in public buildings such as schools and hospitals.

Under the proposals, all such machines would have to contain a certain amount of healthy foods, for example, 30% water and fruit.

Over time that quota could increase, possibly leading to the eventual removal of fizzy drinks, biscuits, and cakes from vending machines in venues which actively promote and teach of a healthy living.

The special advisory group would also like to see more incentives to encourage healthy eating, including potential subsidies and more schemes such as the Bord Bia schools programme ‘Food Dudes’, which has been proven to encourage young children to try different vegetables.

Cliodhna Foley-Nolan, director of human health and nutrition at Safefood, said that fizzy drinks and these foods have been targeted as they are “nutritionally empty”.

“These are the top-shelf of the food pyramid or nutritionally empty foods and when somebody eats too much of these foods and it is part of a lifestyle pattern which includes minimal exercise, it becomes part of a pattern that leads to obesity,” said Dr Foley-Nolan.

“Public awareness is a big issue at play here and a tax would be a wake-up call.

“As people become more used to seeing overweight people and we increasingly see advertisements for the likes of plus-size Communion dresses, we must be careful that we don’t normalise being unhealthy.”

Consultant endocrinologist Donal O’Shea, who also sits on the advisory group, said that this is “about influencing behaviour and about starting discussion”.

“It took eight years of movement to get calorie counts on menus,” said Dr O’Shea. “The food industry will not like a sugar tax one little bit as their fear is that, if this happens on an island, we will be able to show impact quickly — ie, we can look at the weight of children over a certain number of years.

“Their fear would be that it would be replicated at EU level as that would really impact on them. It is at EU and global level that the big brands operate.”

A recent study showed that daily consumption of fizzy drinks increases by 20% the likelihood of acquiring type-2 diabetes.

As the evidence grows linking fizzy and isotonic drinks to weight gain, Dr O’Shea said sports stars such as Ronan O’Gara and Katie Taylor “must consider whether they continue on as sports ambassadors for these brands”.

The special advisory group’s report will be presented to Mr Reilly by the end of the summer.