There is concern that bringing in a tax hike on unhealthy foods will target the less well-off.
The Institute of Economic Affairs is hitting out at plans to bring in 'sin taxes' on food and soft drinks which would cost a typical Irish family around €600 extra per year.
The think tank is critical of the World Health Organisation which is encouraging governments to bring in health levies on 'bad foods'.
Head of Lifestyle Economics at the Institute of Economic Affairs, Christopher Snowdon, made a call on the WHO, saying: "Well I'm suggesting to them to think again about taxes which penalise people who are poor, both in the developing world and in the developed world.
"These taxes are not a very effective way of changing people's shopping habits, let alone people's waistlines or state of health."
Mr Snowdon said this kind of tax is a backward step.
He said: "The effects of any tax like this is invariable regressive, that means it takes a larger share of income from people on low incomes than people on high incomes.
"So, there is an ethical concern on that and the more of these taxes you have the worse that gets."