Footballers from Northern Ireland who want to play for the Republic will have to meet tough restrictions, it was confirmed on Monday.
They will have to notch up two years playing south of the border without interruption or have close family members from there.
The issue centred on the Republic of Ireland's governing body's assertion they are allowed to pick Northern Ireland-born players, even if they do not have family ties with the south.
Controversy arose earlier this year when the Irish FA protested after Londonderry-born Darron Gibson was picked for the Republic of Ireland team.
He was born in Northern Ireland but elected to switch to the Republic after representing the north at Under-16 level.
An Irish Football Association spokeswoman said: "FIFA have said that if we deem any player called into the Republic of Ireland's squad ineligible then we can bring that case to FIFA.
"We can appeal if we think they are going against any of the criteria."
However, clarification of the row has prompted a fresh political fall-out.
Nationalist SDLP Assembly member Dominic Bradley, who represents a constituency on the border with the Republic said it was a ridiculous decision.
"This is totally out of keeping with with the letter and the spirit of the Good Friday Agreement (which paved the way for political power-sharing in Northern Ireland)," he said.
"It seems totally ridiculous that somebody born in Newry, Co Down, as an Irish citizen, can't play for the Irish national team unless they have resided in the Republic for two years.
"They could be playing for Manchester United but would not be eligible to play for their country."
Keen football fan Gregory Campbell, East Londonderry MP for the Democratic Unionist Party, said it would regulate any inconsistencies.
"We should be working towards the position where people want to play for Northern Ireland," he said. "Hopefully this can draw a line under it."
(reopens) A spokesman for the FAI added: "We do not believe there has been any change to FIFA's stated position that any player from Northern Ireland is eligible to play for either Northern Ireland or the Republic of Ireland."