By Mark Simpson
BBC News Ireland correspondent
While the decline in the value of sterling is posing problems for UK tourists bound for Europe, it is providing an unexpected boon for Northern Ireland's retailers.
Some shops are offering direct 'pound-for-euro' exchange rates
As the pound keeps falling, the traffic-jams keep growing with euro-shoppers coming to Northern Ireland for a Christmas bargain.
With some shops offering a straight 'euro-for-pound' exchange rate, the queues are getting longer and longer.
So much so that some local people in border towns like Newry and Enniskillen are annoyed at having to fight their way through the "euro tourists" to get to their nearest shops.
Cross-border shopping trips in Ireland are as old as the border itself but what's happening at the moment is unprecedented. The scale of the influx is staggering.
Take the Asda store in Enniskillen, Co Fermanagh:
- 60% of its customers this month have come from the Irish Republic
- It is the 6th busiest store in the global Wal-Mart chain
Along the border in Strabane, sales were up 54% last week at the local Asda, compared with the same week last year.
Not bad for a store in a town which used to be one of the UK's economic blackspots.
Strabane ASDA manager, Eugene Teague, says: "It's down to the exchange rate and the southern customer just getting in their car and being prepared to drive that bit further."
Last year, a Euro was worth around 70p, now it has soared above 90p.
Most of the cross-border shoppers are making a 30-minute drive from neighbouring towns but there is evidence of some shoppers being prepared to come from more than an hour away, if not further.
They reckon they can save at least 30% on their weekly grocery shop.
At the Supervalu store in Strabane, manager Martin McBrearty not only allows customers to pay in euros but gives them their change in the same currency.
So what are the southern shoppers coming north to buy?
"The big one this year is the alcohol," says Mr McBrearty.
"We're hearing lots of stories about people coming up with trailers, and filling them full of alcohol from the local stores and then scampering across the border again."
The Dublin government is watching the exodus with increasing concern.
Irish Finance Minister Brian Lenihan recently rebuked the cross-border bargain-hunters.
He said: "When you shop in Northern Ireland, you're paying Her Majesty's taxes, you're not paying taxes to the state that you live in."
It was a blunt appeal for patriotic shopping.
However, the large numbers of cars from the Republic parked at northern shopping centres last weekend suggested Irish people are currently more concerned with personal economics than national politics.
One southern shopper in Strabane said: "I would shop in the South if they would bring down their prices and match the prices in the North.
Sterling's decline appears to have fuelled a rise in alcohol sales
"If they were any way patriotic, they would bring down the prices and not be so greedy. In the South they raised VAT, here they cut it."
The VAT rate in the UK is down to 15%, while it recently went up in the Irish Republic to 21.5%.
It is making life difficult for southern retailers.
Paul Bradley, who runs a Eurospar in Buncrana, Co Donegal, has already had to reduce his workforce.
He said: "There are job losses in this area and there's probably going to be more if this exchange rate continues as it is. It just continues to drop day after day.
"I've been in the retail trade for about 30 years and this is the toughest patch I've ever gone through. I'm normally a good sleeper but I'm sleeping less at night now."
The so-called Celtic Tiger economy in the Republic has limped into recession. The procession of shoppers across the border is making things worse.
There is little sign of any sympathy from their northern neighbours. The South's difficulty is seen as the North's opportunity to cash in.
It's not politics. It's simply business.