Publicans and hoteliers in Border counties are worried that a smoking ban could see customers cross to the North.
Ms Julie Gilhooly, who owns the Nuremore Hotel in Carrickmacross, believes a smoking ban will have a serious effect on her business. She argues that her customers will opt to head seven miles across the Border.
"I'm chair of the local Hotels Federation branch, and there's a lot of concern about this," she said. "Some of the hotels are just 50 yards across the Border in the North, and people can puff their heads off if they want to.
"Up to 50 per cent of our weddings come from Northern Ireland. I think I will lose a lot of that business, because couples will just stay in the North. I think they will be worried that their wedding could be split into two parties, with the smokers all banished outside."
Border landlords' worries have been caused by stories emanating from Manhattan bars about the "Jersey effect". This phenomenon has apparently emerged in New York where a stringent smoking ban was put in place in March.
Manhattan workers, it is said, have deserted the bars of downtown Manhattan for Hoboken and other parts of New Jersey, less than half an hour by ferry.
However, Chuck Hunt of the New York State Restaurant Association, which opposed the ban, said there had been no evidence that tourism numbers were down. "There has been a dip in tourist numbers, but this has been because of 9/11," he said.
There are those who feel the ban has had a negative effect on business, especially those businesses which primarily sell spirits and beer. Such claims appear to be borne out by recent company results such as Orient Express hotels, whose landmark bar, the 21 Club, suffered a drop in profits which it blamed on the smoking ban.
Similarly, Heineken said that failure to reach growth targets in the US market was also caused by a drop in demand due to the New York smoking ban.
"Restaurants, though, do not appear to have been badly hit. They've seen a slight change in customer base," said Mr Hunt.
In Northern Ireland, publicans are preparing for a business boom from January 1st. Mr Gary Boylan, who owns the Balmoral Bar in Warrenpoint, Co Down, expects increased business from customers as far away as Dundalk, 18 miles south.
"I definitely do feel there will be a big impact in towns like Warrenpoint and Newry. There has been a lot of talk among publicans about it," he said.
Mr Boylan believes the Good Friday experience is an indication of what will happen: "Busloads from the South go to Warrenpoint Golf Club on a Good Friday just to get a drink. "
However, research in California, where strict anti-smoking laws have been in place since the early 1990s, suggests that the tourism industry has little to fear.
A 1999 report published in the Journal of the American Medical Association found that hotel revenue in about half the states and cities jumped after strict smoking laws were enacted. The study, whose validity was questioned at the time by smoking-rights advocates, also concluded that foreign tourism was not curtailed by restaurant restrictions.