Northern Ireland's deputy leader Martin McGuinness is calling for a vote to unite the two sides of the Irish border as stocks tumbled in the economic and political fallout from Britain's decision to quit the EU.
Ireland has the EU's fastest-growing economy but also more to lose from Brexit than any other member state, with far-reaching implications for its trade, economy, security of energy supplies and peace in British-ruled Northern Ireland.
After 56 percent of Northern Irish voters sought to remain in the EU compared to the 52 percent of the United Kingdom as a whole who voted to leave, Sinn Fein's McGuinness demanded that London call a referendum on a united Ireland.
"The British government now has no democratic mandate to represent the views of the North in any future negotiations with the European Union and I do believe that there is a democratic imperative for a 'border poll' to be held," McGuinness told national Irish broadcaster RTE.
"The implications for all of us on the island of Ireland are absolutely massive. This could have very profound implications for our economy (in Northern Ireland)."
The call from Sinn Fein, Northern Ireland's largest Irish nationalist party, was rebuffed by pro-British First Minister Arlene Foster and Irish Prime Minister Enda Kenny, who said there were much more serious issues to deal with.
Ireland's central bank had warned that a withdrawal would hurt economic growth and jobs and significantly impact the financial sector, while a government-commissioned report found it could cut trade with Britain by at least 20 percent.
Finance Minister Michael Noonan, who earlier this week said an estimated cumulative Brexit-related hit on the Irish economy of as much as 1.6 percent of GDP would be "containable", said the outcome would not derail his immediate budget plans.
Ratings agency S&P said Brexit had no immediate impact on Ireland's sovereign ratings and it expected the Irish economy to stay resilient enough to withstand the negative impacts.
Brexit may not be all bad for Ireland, and Noonan said there may be some upside if companies keen to stay in the EU moved to Dublin from London.
But of most concern to Dublin is the impact on Northern Ireland, which has the only land frontier between the UK and the rest of the EU.
It was marked by military checkpoints until a 1998 peace deal ended three decades of sectarian violence.
Foreign Minister Charlie Flanagan told Reuters this week that the reintroduction of a hard border would have to be considered in any negotiation and that the return of controls, for customs or security, could pose a difficult challenge for the peace process.
Kenny said Ireland would do its utmost to keep the country's decades-old common travel area with Britain.