Fine Gael has claimed publicans are making profits of up to 1,000% on some non-alcoholic drinks.
The party said a survey it conducted in 47 Dublin pubs found that a glass of water with a dash of lime could cost up to €4.70, with the dash of lime alone costing up to €2.
Spokesman Phil Hogan said: “It is disgraceful that publicans are seeking to exploit the soft drinks market to the extent that they are.”