Their displeasure is down to the fact that it will contain Northern representation.
The DUP's East Derry MP Gregory Campbell has said that the establishment of the committee demonstrates an extraordinary level of arrogance on the part of the Irish Government.
This utterance by Gregory comes after the leader of Seanad Eireann, Fianna Fáil's Donnie Cassidy proposed that there be permanent Northern Representation in the Seanad.
Now I understand that many people have issues with the Seanad, myself included, however this can only be another positive step.
The all-party Oireachtas committee on the Constitution has already made clear the need for more Northern Representation in the Dáil and the Oireachtas in general.
Prodiban protagonists like Gregory may find that uncomfortable however this is the road in which we are headed.
It's only going to get worse for people like Gregory, All-Ireland cooperation and integration is the way forward and it is the de facto policy of both governments.
It's about time that Unionist's started to accept this obvious reality.