Any barrier on free movement of EU workers would damage our manufacturing prowess, says trade group
Employers have a "significant" reliance on workers from the EU and any barrier to free movement would be "detrimental to Northern Ireland's manufacturing renaissance", it's been claimed.
One study has said the UK is reliant on EU workers, especially in manufacturing, accommodation and food services.
EU employees are generally educated to a higher level than UK-born staff, with only 15% having left formal education before the age of 17 compared with 44% of those born in this country, it was found.
And it's Northern Ireland's food manufacturers and processors which have the most to lose from a Brexit, according to Stephen Kelly, chief executive of Manufacturing NI.
EU employees represent 5% of occupations such as managers, directors and professionals, although high numbers also work in jobs requiring no formal qualifications such as cleaners and shelf-fillers, according to research by the Social Market Foundation and Adecco.
There are currently 1.6 million EU workers employed in the public or private sectors, making up 6% of all UK employees, said the report.
Stephen Kelly of Manufacturing NI said: "Our food processing in particular has enjoyed the benefit of having workers from other parts of the EU, working on processing lines.
"In addition, the growth of some of our engineering firms has been supported by the arrival of talented, experienced and productive welders.
"The free movement of labour has also helped our companies in Northern Ireland with work across Europe, and any barrier to that, in our view, would be detrimental to Northern Ireland's manufacturing renaissance.
"I'm sure the likes of the big processors would have a lot of EU labour, as do other parts of manufacturing."
And he said it was a "two-way street" with workers from Northern Ireland moving to other parts of the EU for employment.
Many Northern Ireland manufacturers have plants elsewhere in the EU, including Delta Packaging in west Belfast.
The company - which makes packaging for firms including McDonald's, Kellogg's and KFC - opened a new factory in Poland last year.
Speaking about the new report, Adam Hawkins, managing director of the Adecco Group, said: "This research raises serious questions about the potential impact of Brexit. With 1.6 million EU workers currently working in the UK, making up 6% of all UK employees, thousands of businesses could be left in limbo for years following a vote to leave.
"Uncertainty is bad for business, particularly those looking to hire and invest in the future.
"The recruitment industry has seen a significant slowdown in the number of businesses looking to hire permanent staff as we draw nearer to the referendum.
"Any change to the UK's relationship with the EU could hinder UK businesses' ability to attract the workforce needed for our industries."
Nigel Keohane, director of research at the Social Market Foundation, said: "This new research shows the extent to which UK organisations employ workers from the EU."