The revelation was published in a 131-page contingency action plan document published the evening of December 19 — it stated existing co-operation with British police would be compromised if the UK lost access to European databases involving DNA, fingerprints, vehicles, criminal records and airline passengers.
The prospect of the UK dropping out of the European arrest warrant system would also mean criminals could enter the Republic, commit a crime and return to Northern Ireland without fear of extradition.
"The Irish government would work with the British government as a member of the EU27 but also a neighbour and close friend, to minimise economic and social disruption. However, we are under no illusions as to the difficulties that would arise or the challenges involved in addressing them," the document stated.
He added considerable current planning concerned the supply of medicines, of which there is currently a four- to six-week stockpile, due to potentially significant disruption to aviation and road haulage, as well as delays to ferries and exports to Britain. There would be particular pressure on sectors such as agri-food, fisheries, aviation and road transport, pharmaceuticals, electrical machinery, retail and wholesale businesses.
The government is also concerned about EU citizens moving between Ireland, Northern Ireland and mainland Britain.
"There would also be significant issues for citizens' rights, free movement of people, labour and skills shortages, and provision of cross-border public services that would have to be tackled by all the relevant parties," it said.