PJ Carroll, the Irish subsidiary of British American Tobacco, has said over 200 million cigarettes it sells a year will be affected by the upcoming ban on menthol cigarettes.
The menthol cigarette ban, which takes effect on May 20, covers cigarettes which use flavours to relax the airways and make smoking easier on a person's throat.
The change follows the completion of a four-year phasing-in period under a 2016 EU directive on tobacco products.
Simon Carroll, country manager of PJ Carroll, said his company currently has around 50% of the menthol cigarette market, accounting for 200 million cigarettes. Brands it has control of in this area include Consulate, Vogue and Pall Mall.
"It's going to have a big impact [on output]," he said. "We are just around half [of the menthol cigarette market].
"It is probably just over 200 million cigarettes of ours affected by this a year, so it's a big number.
"It is going to impact us dramatically, but again it is hard to know what the monetary value will be until we see what plays out fully with what consumers choose to do.
"We can only give them real alternatives that they can choose to have.
"Hopefully, if they choose to go vaping, they choose ours, but if they choose combustible cigarettes, they choose our brands, too. It's a wait-and-see." Despite the potential effect on output, Mr Carroll is hopeful that the ban will present an opportunity to further the take-up of his company's vaping devices.
According to Mr Carroll, British American Tobacco has invested around $3.5bn into its vaping category. Brands sold by PJ Carroll include Vype pens and Cirro vaping liquids.