The North's First Minister Peter Robinson has said businesses north of the Border had every right to try and entice shoppers from the Republic.
“Let’s be clear, this is swings and roundabouts. There have been many occasions where this has worked in the other direction, it worked in terms of fuel and aggregates when that very clearly damaged the prospects of businesses on our side of the border,” Mr Robinson added.
He said: "Some in the South have said it is unpatriotic to shop in Northern Ireland, but in the spirit of North-South co-operation, I am happy to offer a warm welcome to all of our visitors from the South."
"In truth, it is good for us all. Northern Ireland gets a significant economic boost, and people in the Republic might save enough on their shopping to help pay their higher taxes and their health bills."
Mr Robinson pointed to different prices for fuel as an example of retailers in the Republic benefiting.
"It worked in terms of fuel aggregates when very clearly it damaged the prospects of businesses on our side of the border. I encourage people to come to Northern Ireland and am delighted that they built all those good roads so that people could come up quickly to Northern Ireland," he said.
Deputy First Minister Martin McGuinness said residents in the Border counties had always proved themselves adept at locating the best deal.
“We all know that human nature clearly tells us that over the course of many years people in the border areas and indeed people wider afield will travel almost anywhere to get a good bargain,” said the Sinn Féin deputy leader.
An already steady flow north by shoppers in the Republic is likely to be boosted by recent VAT changes. From December 1st, the VAT rate in the North will drop to 15 per cent, a fall of 2.5 per cent while the VAT rate in the State was increased by 0.5 per cent to 21.5 per cent in the Budget.
Yesterday businesses in Drogheda, Co Louth started a campaign to urge the Government to reduce the rate of value added tax (VAT) to 15 per cent to help them compete with retailers north of the Border.
The Drogheda and District Chamber of Commerce is leading the call for the reduction in VAT, claiming it will stimulate the economy and help stem the flow of shoppers to Northern Ireland.
In an open letter to Minister for Finance Brian Lenihan and Tánaiste Mary Coughlan yesterday, the chamber called on them to “act urgently” to assist the commercial and retail sectors in the State to “stem the flow of income and sales North to the jurisdiction of the UK government”.
“On Monday next, December 1st, we in this part of the island of Ireland increase our VAT rate from 21 per cent to 21.5 per cent while the Northern Ireland economy sees a reduction from the present 17.5 per cent rate to 15 per cent, ignoring all the other negative factors which mitigate against us,” wrote chamber president Patricia Rooney.
Ms Rooney said Belfast City Council and other authorities all over Northern Ireland are “four-square behind their business sector and have organised a Republic-wide advertising campaign to attract the southern shoppers into their stores and hotels and restaurants with even more incentives”.
The chamber will launched a website yesterday to promote its 'Drop the VAT' campaign.
Superquinn said on Wednesday the retail sector faced substantial job losses after Christmas due to the number of shoppers opting to travel to the North.
The National Consumer Agency has found a margin of up to 30 per cent in food prices on either side of the Border.