Sinn Fein has hit back at the Irish Government after an internal government note claimed major electoral law changes would be needed to give people in Northern Ireland a vote in the European elections next year.
After Brexit, Ireland's total representation will rise from 11 to 13, while Northern Ireland will lose its three seats in the European Parliament.
Sinn Fein has called for the new MEP seats to be given to Northern Ireland and says independent legal advice contradicts what the Irish government is saying after it identified a series of obstacles.
A Sinn Fein spokesperson said: "GUE/NGL (European United Left - Nordic Green Left) European Parliamentary Group the group Sinn Fein sits with in the European Parliament, recently commissioned independent legal advice on this proposal which proved there is no legal or constitutional barrier to the Irish government allocating the seats to the north.
"The creation of an extra-territorial constituency of Northern Ireland in the EP elections would be consistent with international and comparative practice across the globe.
"The new constituency should be preferred to a system which allocated the votes of Northern Ireland residers to existing Irish constituencies.
"This can be achieved through the amendment of the current constituencies list. A new constituency of Northern Ireland can be created and allocated two seats."
The internal Irish government note has claimed, however, that major changes to Ireland's electoral laws would be needed: "From a practical franchise perspective, there would be a number of challenges associated with such a proposal given our electoral laws, as they currently stand, do not provide for voting from outside of the State, except in very limited circumstances," the note reads.
"Because of this there would be a need to set up an electoral register for such a purpose and to establish criteria around the eligibility to vote.
"Clarity would also be needed around who would maintain the register. Currently each local authority compiles and maintains a register of its own administrative area.
"Constituencies would have to be agreed, and it would also have to be agreed how a person would vote in practice, for example with a postal vote."
Last week, Ireland's Minister of State for European Affairs Helen McEntee confirmed the extra two seats would represent areas south of the border, though she declined to be drawn on the Sinn Fein demand for the extension of voting rights north of the border.
DUP MEP Diane Dodds has previously said that retaining representation for Northern Ireland residents in the European Parliament would violate the Good Friday Agreement's principle of consent.