The Taoiseach Enda Kenny has outlined why he thinks a British exit from the EU would be bad for both Ireland and Britain.
Addressing the Confederation of British Industry Annual Conference in London, Mr Kenny said that given the overlapping interests of the two countries, Ireland regards the possibility of a 'Brexit' as a "major strategic risk".
Mr Kenny told delegates "Ireland's recovery is good news for Britain".
"About €1bn worth of goods and services are traded between our two countries every week. This is not one-way traffic. The UK exports more to Ireland than it does to China, India and Brazil combined".
"In fact, we are the UK’s 5th largest market".
"There are almost 100 UK companies based in Ireland that are backed by our Inward Investment Agency, the IDA. These employ almost 7,000 people," he added.
He also said he has "no doubt" that continued British membership of the European Union is "good for Ireland and for relationships on these islands".
"Moreover, I believe that continued British membership of the EU is in Britain’s own best interests. But that is for the British people to decide".
The case for that position is being made effectively here by groups and individuals directly involved in the issues as they affect Britain".
"The stakes are too high for the voice of business not to be heard in this debate", Mr Kenny added.
He says the Irish Government hopes that an exit from the EU by the UK will not materialise.
The British Prime Minister David Cameron has promised to hold an 'in/out' referendum on British membership of the EU before the end of 2017 - with concern mounting about what the result could mean for Ireland.
It comes as Mr Cameron prepares to make a list of demands for reform in a letter to the President of the European Council, Donald Tusk on Tuesday.
This week marks the beginning of formal negotiations about Britain's relationship with the European Union ahead of an in/out referendum on its membership.
Other EU countries have previously complained about a lack of detail from Mr Cameron and asked him to put his demands down in writing.
One-on-one discussions with other EU member states and senior officials will begin a week after Tuesday's long-awaited letter to Mr Tusk.
Mr Cameron has been heckled by protesters during a speech to business leaders.
Anti-EU campaigners challenged him as he spoke at the Confederation of Business Industry conference - chanting "CBI, Voice of Brussels".
The 19-year-olds said they had "posed as businessmen" to trick their way into the Confederation of Business Industry event where the Mr Cameron was speaking.
Phil Sheppard and Peter Lyon, who are from Students for Britain, held up a banner saying "CBI = voice of Brussels" and chanted slogans lambasting the organisation for what they claim is a pro-Brussels stance.
The two described the experience of confronting Mr Cameron as "terrifying" but said they had to protest because the CBI was too pro-Brussels.
They said it did not represent a number of small and medium-sized businesses who felt that Britain's membership of the EU hampered rather than helped.
