A British exit from the European Union, or "Brexit", would create serious difficulties for Northern Ireland, Taoiseach Enda Kenny warned on Monday.
The State has more to lose than any other EU member if the UK, a key trading partner, votes to leave the union at a referendum due to be held by the end of 2017 .
Irish proponents of the UK’s EU membership have warned that an exit could damage trade in Northern Ireland and inflame political tensions if it leads to more border controls.
Mr Kenny, in London to meet British prime minister David Cameron, told a news conference the referendum had become a critical issue for the State but that he believed all of the UK's demands for revised terms could be met.
“From our perspective it would create serious difficulties for Northern Ireland and I don’t want to see that happening,” Kenny said.
Early referendum
Earlier, the leader of the main campaign for Britain to stay in the European Union had urged British prime minister David Cameron to call an early referendum on the UK’s membership of the 28-nation bloc.
Britain Stronger In Europe chairman Stuart Rose asked "why would you want to wait?" if the prime minister achieved a deal on his reform demands at February's crunch summit of EU leaders.
The former Marks & Spencer boss sought to highlight the trade benefits of EU membership as he insisted debates over migration should not be allowed to “dominate” the upcoming contest.
Lord Rose released analysis suggesting the EU is worth an average of £670,000 in extra trade for each business that exports or imports goods within the bloc.
The former Marks & Spencer boss acknowledged the EU was “imperfect” but argued that its benefits to the UK outweigh its costs by a factor of 10 to one and warned voters that Britain faces “uncertainty” over its future if it leaves.
Lord Rose's warning came as pro-Brexit group Vote Leave seized on the findings of a study that claims the single market has had "no discernible benefit" for UK exports and has proved "not far short of a disaster" for Britain.
Research from thinktank Civitas found UK export growth in the single market area was 22.3 per cent lower following the creation of the EU in 1993 than it would have been had it continued at its trend rate during the common market years of 1973-92.
Vote Leave chief executive Matthew Elliott said: "The unquestioning mantra that the single market has been good for British trade is wrong and should be challenged as this research makes crystal clear."
EU renegotiations
The British prime minister will head to Brussels next month to try to finalise renegotiations of Britain’s relationship with the EU before putting the deal to the country in a referendum before the end of 2017.
Lord Rose said he hoped Mr Cameron would secure a deal allowing an early referendum - which some observers believe could come as soon as June.
On a tour of the Brompton Bicycles factor in west London, he said his campaign would be ready for a June vote.
“We will be ready for any eventuality,” he said. “Once we have a deal, whenever that deal might be, let’s assume it is in February, why would you want to wait?
“I think there is enough time to get the information out, to get the facts out, to have a healthy debate. Why would you want to wait?”
He said he would be “happy to join forces” with Mr Cameron, who has indicated he will play such a prominent role in selling any new deal he achieves that voters will be “sick of the sight of me”.
“I would expect that deal to be sold very hard by the government once that deal has been done,” Lord Rose said.
“I’m very happy to join forces with the prime minister in supporting him in what he has done. I think it is a tough negotiation, let’s see what we get from that negotiation.
“As we come towards the period of the referendum we will be very happy to join forces.”
Although Mr Cameron has repeatedly insisted that he will “rule nothing out” if he fails to secure a deal, Lord Rose said: “I have heard nothing the prime minister has said which suggests he would be voting for an exit.
“I’m confident that he will get a deal and, as far as I’m concerned, although I do not think this is a perfect relationship, the UK and EU have always had a slightly combative relationship, but it is a relationship that benefits both sides.
Britain Stronger In Europe is highlighting research by the Centre for European Reform that found Britain’s goods trade with the EU is 55 per cent higher as a result of its membership.
The “EU effect” was worth around £133 billion to the 200,000 export and import companies in the UK in 2014, it said.
Reuters and PA