Members of the Northern Ireland Assembly are to be banned from becoming members of Dáil Éireann at the same time as they are sitting at Stormont.
The move to outlaw potential cross-border political double-jobbing was outlined during a speech by Britain's Queen Elizabeth at Westminster.
Recently, the main parties at Stormont have reduced the number of their politicians double-jobbing as Stormont MLAs and Westminster MPs.
However, three high-profile politicians - two DUP Stormont ministers and SDLP leader Alasdair McDonnell - still perform both roles.
Northern Secretary Theresa Villiers has already announced that the practice is to be banned from 2015, and it is to be extended to the Dáil.
During consultations on the Westminster proposals, it was pointed out that while it was envisaged that MLAs could no longer be elected MPs, there was hypothetically nothing to prevent them becoming TDs, but that potential loophole is to be closed under new legislation.