Farmers are calling for laws to make sure Irish whiskey companies are using home-grown ingredients.
Irish whiskies were recently granted geographical indicator status, which means, similar to Champagne in France, drinks can only be called a 'whiskey' if they are distilled in Ireland.
However, Irish farmers are pushing for a change in European laws that will ensure all ingredients used in whiskies are from the island.
Internationally recognised stars such as UFC star Conor McGregor and U2's Bono have heavily invested in local distilleries in the past year.
But farmers say Irish-based companies are using grains, such as barley and maize, which are being imported from neighbouring countries.
Irish Grain Growers chairman Bobby Miller believes producers aren't genuinely Irish unless they use homegrown crops.
He said: "Irish whiskey is being made from imported grain. Barley is being imported but the biggest problem is maize.
"In the last few weeks the whiskey industry has received geographical indicator status from the EU, that means no one can copy the production of whiskey, but there’s no mention of the grains that have to be used in the process."
He told the Irish Daily Mail: "You can have a whiskey that has no Irish ingredients in it whatsoever and it’s still an Irish whiskey.
"The Whiskey Act says you have to produce the whiskey here on the island of Ireland, process it on the island of Ireland and store it for three years and one day and then you can call it an Irish whiskey."
Mr Miller admitted that the companies aren't doing anything illegal, but claimed that switching to Irish ingredients would only cost consumers 1 cent per bottle.
He added: "The question to ask is: are they making the drinker aware of where the ingredients come from?
"It would cost the person buying the whiskey off the shelf maybe an extra 1c on a bottle."
Despite the calls, the Irish Whiskey Association insisted that some ingredients, such as peated malt, are not available in Ireland.
Spokesman William Lavelle said: "Irish whiskey distilleries are sourcing nearly all of their malt from Irish malting houses and unmalted barley from Irish tillage farmers.
"The Irish whiskey industry must import peated malt, primarily from Scotland, due to the lack of peated malt production in Ireland.
"Small quantities of some speciality malts are also imported."
McGregor's new Proper No Twelve helped sales of Irish whiskey in the US to hit over $1billion last year for the first time, it was reported last week.
The 30-year-old's brand, which launched last September, has sold over 200,000 cases.
Proper No Twelve has been contacted by the Irish Mirror for comment.
