Workers north, south and over the water may face 'race to the bottom' in pay and conditions
Unions fear that Irish workers may become victims of Brexit if "unscrupulous" employers and a far-right Conservative Party leadership begin a "race to the bottom".
And Brexit Britain is likely to be a far less welcoming place for workers as social welfare benefits are set to be stripped, border controls mounted and EU employment rights law faces an uncertain future.
In addition, there is little evidence that the UK's departure from the EU will push up wages, despite claims by David Cameron's likely replacement, Boris Johnson, that salaries have been driven down by immigrants.
But there may be a jobs boost at home as investors that were eyeing our nearest neighbour may see Ireland as a safer bet.
Siptu's manufacturing division is worried about an immediate impact on workers in the Republic who are highly vulnerable to any upheaval in business with our biggest trading partner.
It warned that employers may see an opportunity in the "dangerous uncertainty" in the manufacturing industry to drive down labour costs as exports become more expensive due to the devaluation in sterling.
The division's organiser, Gerry McCormack, called on the Government to immediately begin talks with the UK to stabilise the trade in which 16pc of goods manufactured here are exported to the UK.
"Always, in such periods of crisis, some unscrupulous employers will perceive an opportunity to attack workers' wages and conditions," he said.
The general secretary of the Irish Congress of Trade Unions, Patricia King, also expressed fears that a "race to the bottom" that has already driven down wages and living standards across the Border may take hold here.
A total of 25,000 workers who cross the Border from Northern Ireland to work in the Republic may face passport controls, although their wages are likely to have greater purchasing power in the North, at least initially. But newcomers may lose their automatic right to work here.
Anne Frawley, a senior consultant at Mercer, raised the prospect that British expats working here may face restrictions in accessing our healthcare system.
Workers thinking of joining the 407,000 people who hold Irish passports in the UK may have second thoughts, despite assurances by the Leave campaigners that the Irish community will be unaffected.
David Cameron had already struck a deal with the EU that migrants would not get full social welfare benefits for four years. He assured the Taoiseach that Irish nationals would not be affected, although the legal implications of this have been questioned.
However, there is no guarantee that the new order will live up to that promise and more severe restrictions could be imposed.
It is also likely that restrictions will be placed on the number of EU workers within the UK workforce, which will have significant implications for Irish companies with a UK workforce.
There appears to be little evidence that workers in Britain will enjoy a significant wages boost if immigration dries up. One of the Leave campaigners' big arguments was that immigration was depressing wages.
But Boris Johnson was caught out on this argument by former Scottish First Minister Alex Salmond when he claimed that a Bank of England study had shown that for every 10pc increase in immigration, there was a 2pc reduction in wages.
Mr Johnson was forced to admit he had not read the study, but even more tellingly, Mr Salmond, who said he had read it, revealed that it showed that a 10pc rise in immigration would cause a drop in wages of just a third of one pence.
There may also be implications for Irish workers in Britain in terms of EU employment rights legislation. The working-time legislation, which is a Conservative bugbear, may be repealed or amended. It means that an employee's average working week should not exceed 48 hours.
But there is unlikely to be an immediate 'bonfire' of the legislation as Britain will have to negotiate its future relations with the EU. The British government may decide there is little political advantage in dismantling employment rights, such as paid holidays, parental leave or legislation that forbids employers from discriminating against employees on grounds of disability, age or sex.