The head of the country’s biggest business body, Ibec, said flexibility is needed for his country – or Irish EU exit could be on the cards.
Danny McCoy warned state aid, fiscal rules and a common consolidated corporate tax base would be on a list of issues on which compromise would be demanded.
In Ireland, Ibec wants Europe to ease fiscal rules so more can be spent on capital infrastructure.
Ibec also insisted exceptions are needed for the Irish agri-food and drink sector from EU state aid rules.
Mr McCoy told the Irish Independent: "We want to stay in the EU 27, but the costs of us staying in the EU 27 could be very heavy if the EU 26 don't allow us the capacity to stay in and compete.”
Concerns were raised about Ireland’s future with the EU as it pushes for joined-up policies and unifying rules for member states.
For Ireland, which is much smaller than major nations like Germany and France, taking on a “one size fits all” approach, could be a bad idea.
European Commission (EC) member in charge of Brexit negotiations with Prime Minister Enda Kenny Brexit debate in pictures Mon, April 17, 2017
The debate in the European Parliament in Strasbourg will focus on key issues of the Brexit talks including reciprocal rights for EU citizens, the peace process in Northern Ireland and trade
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Former leader of the UK Independence Party (UKIP) Nigel Farage (L) gestures as he speaks with EU Commission president Jean-Claude Juncker (R) prior to a debate on the conclusions of the last European Council, at the European Parliament in Strasbourg
If we don't appeal to that force majeure issue and get this one size does not fit all, then I think we're in a conflict with the other EU 26
Mr McCoy said Britain and Ireland have disproportionately experienced EU migration and the application of single rules could cause issues.
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He feared problems with new arrivals if the government is not able to spend more to deal with the state's infrastructural deficit.
Mr McCoy said: "If the infrastructure isn't building fast enough, people will feel crowded out in the playground, or from the school, and that's what led to the [UK] referendum.
"If the fiscal rules are the things that stops you from taking the resources you have and building that infrastructure fast enough, we're hurtling down for exactly the same kind of referendum decision here if we don't wake up.
"If we don't appeal to that force majeure issue and get this one size does not fit all, then I think we're in a conflict with the other EU 26."
Concerns have been raised with Brexit negotiator Michel Barnier
John McGrane, head of the British Irish Chamber of Commerce, said: "We need to have a conversation about where is the European Union taking us.
"We have to feel completely secure in our ability to have a conversation that appreciates absolutely what EU membership has given us, and yet be able to sa … is the EU as strong as it needs to be, and delivers in this context a competitive platform for businesses to prosper globally, but also to take care of Ireland's utter connectivity to the UK."
Earlier this month Ibec bosses met with Brexit negotiator Michel Barnier, who is fighting the best case for the remaining 27 member states.
Mr McCoy said Ireland’s issues have been made plain to the EU.
He said: “There is a welcome recognition in Brussels of the unique risks Brexit presents to Ireland."