Martin Mulligan, who owns Topaz Londis in Athlone, Co Westmeath, said door-to-door sales of illegal tobacco products are flourishing, costing the state millions of Euros in lost revenue and threatening the existence of stores like his.
He believes that the Irish tobacco display ban, which came into force last month, will only make the problem worse.
"The black market is absolutely huge here," Martin told The Westmeath Independent. "We have to hide our products away, but they are openly on sale on the streets of Athlone.
"Cigarettes are being brought in at 35c (30p) a packet and then they are selling them on at e4 (£3.44) a packet. Our price is e8.45 (£7.28)," he said.
Martin said tobacco accounted for 30% of his trade, but lost footfall would also hit newspaper, lottery and confectionery sales.
"Smuggling causes lost sales of everything and our trade stands to lose 5,000 jobs as a result. Our livelihoods are under a considerable threat," Martin added.