Ibec has launched a poster campaign in Dublin Airport to highlight to people travelling to and from the UK the "compelling, positive case" for Britain remaining in the EU.
The media campaign by the group that represents Irish business will run right up to the vote on Thursday 23 June, and is targeted at voters in Britain with Irish family and business connections.
It will highlight the deep economic ties between the two countries and the risk that the UK leaving the EU would pose to this relationship.
Speaking at the launch in Dublin Airport, Ibec CEO Danny McCoy said: "Deep historical, geographic and commercial ties mean Ireland has a lot to lose if the UK votes to leave. Not only will the UK economy suffer, Ireland will also be badly affected.
"The UK's EU membership is of key strategic importance to Ireland and Irish business. We have been close allies in Europe across a wide range of areas and we are stronger when we work together. An EU without the UK would be a lesser Union.
"A UK exit would send Ireland, Britain and Europe into uncharted and treacherous waters. The value of sterling has already fallen significantly, a vote to leave would prompt a further significant depreciation, heaping pressure on businesses trading with the UK. This is in addition to the countless other risks that would arise during and after the period of a negotiated exit. A UK departure would be a blow to the Irish recovery and result in a protracted period of uncertainty. It would undermine Europe's ability to act collectively and decisively in the world and would push the EU back into a damaging period of crisis management, at a time when it should be looking to the future."
Mr McCoy set out four key risks for Ireland if the UK votes to leave the EU:
Exchange rate: This is the most immediate risk. In the aftermath of a possible Brexit the sterling/euro exchange rate is likely to move toward or above parity. This would leave Irish firms selling into the UK market 30% less competitive by June than they were in January through exchange rate movements alone.
Trade: Any new UK-EU arrangements may undermine free trade. An agreement would take at least two years, but is likely to take much longer. This would bring a level of uncertainty for Irish firms exporting to Britain in the short term impacting on employment, investment and export plans. The risk to trade flows has been underestimated because of the very significant knock on impact that changing investment patterns could have on trade. Ireland's investment-friendly business model is particularly exposed.
Investment: There are potential opportunities for Ireland from a Brexit. UK-based corporates and financial sector firms will need a home within the European single market. Dublin may be in a prime position to benefit. However, Brexit would also mean that the UK would no longer be subject to state aid rules when competing for FDI or encouraging indigenous business. The UK government might introduce enhanced business and investment supports in order to prevent capital flight and attract FDI.
Regulator divergence: Firms operating within both the EU and UK markets would also have to deal with the prospect of regulatory divergence over the years ahead. For services companies operating in both jurisdictions the impacts are potentially greater as it is unlikely the UK would have to abide by common standards in their domestic services market.