IRFU Chief Executive Philip Browne has hit out at the Welsh Rugby Union but believes that sides must work together to resolve the Celtic League row.
"In taking five weekends out of the Celtic League to facilitate playing in the Anglo-Welsh Cup, the WRU have ripped the heart of it," he said.
"Their fixture document does not address the fundamental issue of not playing on international weekends.
"Scotland, for example, simply does not have enough players to play then."
Browne went on to say that Wales have emasculated the Celtic League on the back of the Anglo-Welsh Cup.
"We must have a meaningful Celtic League to make it commercially viable," Browne told the Irish Times.
"Wales are claiming the nuclear option; accept our decision or else.
"Wales want to have the Powergen Cup on the three weekends leading up to the Heineken Cup in October and again when the competition resumes in December.
"This rips the heart out of the Celtic League and means that the Scottish and Irish would finish their seasons a week earlier than the Welsh.
"I'm not quite sure how we are going to resolve the impasse. There is no movement in Wales who have made the Anglo-Welsh Cup a priority and in doing so relegated the important of the Celtic League.
"There will have to be some accommodation on both sides. We have no problems with them playing in the Powergen Cup, just the dates in question.
"We have to create a professional season and we'd prefer that to involve a Celtic League at the centre of it."