Irish businesses exporting to the UK are already 15% less competitive than before the Brexit vote.
That is according to IBEC, who is calling on the Government to take measures to safeguard competitiveness.
The organisation has said a survey of Irish businesses shows that they can't compete with the rapid currency fluctuations and competition from UK based companies.
It is also now cheaper for UK companies to export into Ireland.
Fergal O'Brien, Director of Policy with IBEC, has said there are still many unknowns: “We can only focus on those issues on which we have control over, and the key to that has to be the cost of doing business.
“We may well see the UK government provide supports to industry, we may well see the UK government cut its own taxes and our Government needs to stand ready to react to that.
“The UK could actually become quite aggressive in supporting business post-brexit and Ireland must make sure we are in a place to respond.”