RTÉ has pledged to “explore” why viewers in the north have been listed as international customers and prompted to pay a 120 euro subscription fee to access the RTÉ player app.
Fianna Fáil TD for Cavan-Monaghan, Brendan Smith, said he had written to senior management at RTÉ about the matter.
He said: "They (northern users) no longer have access to RTÉ Player app, which they have been using since its launch, and are instead being forced to change to an 'international' version of the application."
"This new app has greatly reduced access to domestic programmes, is clearly intended for overseas users and requires a 120 euro subscription to unlock content that is free on the regular service."
The Fianna Fáil Parliamentary Party Chairman added: "For now, I’m prepared to give RTÉ the benefit of the doubt and hope that it is simply a mistake made by some over enthusiastic programmers unfamiliar with the all-Ireland dimension required of RTÉ."
The TD for Cavan-Monaghan said RTÉ "has an obligation to its viewers across all thirty two counties."
He said: "The idea that 'domestic services' would be limited to residents in the Republic only would be a seriously retrograde step and would represent a repudiation of the good work and commitment of the station over generations."
"Citizens across our country, north and south, should have the same access to RTÉ programming and the same services."
Mr Smith added: "If RTÉ are unwilling to commit to a speedy reversal of the current situation, I will be bringing this up with the Minister for Communications at the earliest opportunity and will be pursuing it in the Dáil when it reconvenes."
The Republic’s state broadcaster said that restrictions within the iTunes system meant that that northern users were being redirected to download the international version of the app.
A spokesman said: "RTÉ is aware of the issue and is currently exploring how this can be resolved. RTÉ takes its remit to serve audiences on the island of Ireland seriously."
"RTÉ International Player was introduced earlier this year, via iOS (Apple) app, to make a wider range of RTÉ content available to people outside the island of Ireland; it includes more than 100 hours of free content and an option to pay for additional content."
The RTÉ spokesman added: "Because of restrictions within the iTunes system, people in Northern Ireland with a UK iTunes account are being redirected to download RTÉ Player International on iOS (Apple). Access via desktop and Android is not affected."
