Councils along the Irish border have met in County Fermanagh to discuss the impact of Brexit.
They discussed a report which sets out some of the risks and opportunities to the border area after the UK leaves the EU.
The study found that some of the weakest economies on the island of Ireland are along the border.
These areas are most in need of protection against any negative impacts of Brexit, the report added.
The Ulster University Economic Policy Centre study says while the proposed shape of Brexit is becoming much clearer, the risk posed or opportunities presented remain a matter of speculation and will need to be made subject to revision on an ongoing basis.
It states that border businesses rely more on the 3bn euros (£2.5bn) cross-border trade and Republic of Ireland/GB trade rather than exports to the rest of the EU or further afield.
This trade is dominated by sales of goods by the agri-food, building materials and chemicals sectors which are exposed to risks of significant tariffs and non-tariff barriers, such as an end to common standards.
The report says EU funding, which is worth upwards of 5bn euros (£4.2bn) to the border corridor to 2020, will depend on mitigation from other funding sources.
This money, ranging from Common Agricultural Policy and skills development programmes, to cross-border and peace funds, will end for Northern Ireland after Brexit.
Foreign direct investment has delivered more than 7,000 jobs to the area in the past five years, and Brexit will bring risks and large opportunities depending on access to the EU market, the report says.
It says “like cross-border shopping, this is a competitive area for councils although it may need to be explored how to adopt a joint approach to sell the corridor as a whole in the context of Brexit”.
In 2015 almost a million cross-border journeys were made every week at border crossings to access work, education and other services.
Freedom of movement is also critical for the more than three million visitors to the border corridor in 2015 whose expenditure amounted to more than 600m euros (£507m).
The report recommends that councils work collectively as a lobby group to show that the border corridor is going to be most affected by Brexit and to have their voices heard in the negotiations.
Border counties hold Brexit meeting}