The Irish Rugby Football Union has a released a statement saying the provinces will not be participating in future tournaments which do not have the full approval of the International Rugby Board.
As the saga over club tournaments and a breakaway from the Heineken Cup continues, the Irish body have made clear their desire to avoid division in the club game in Europe.
The statement read: "The IRFU and its clubs remain fully committed to the development of a pan European Rugby Competition and we welcome the recent comments made by the IRB Chairman, who confirmed that a pan European tournament remains the goal of the IRB. We are confident this can be achieved.
“Our focus now is to work collaboratively with our colleagues across Europe, encouraging all parties to come to the table in order to engage in and conclude negotiations as speedily as possible.”
The Welsh and Scottish RFUs have also released similar statements.
"Scottish Rugby wishes to clarify that its clubs will not be participating in future tournaments which do not have the full approval of the International Rugby Board or the relevant national rugby unions," the SRU said.
While part of the Welsh statement read: "The Welsh Rugby Union wishes to clarify that it will not sanction any of its clubs or regions participating in future tournaments which do not have the full approval of the IRB and the WRU."
The statements follow plans announced earlier this week for a new Rugby Champions Cup next season led by top English and French clubs.
Premiership Rugby and Ligue Nationale de Rugby say they have no interest in resuming negotiations with European Rugby Cup over a new tournament agreement for the Heineken Cup and Amlin Challenge Cup competitions. The current accord expires next summer.
Talks are not planned to resume untiil October 23, and ERC has appointed a mediator - Canadian lawyer Graeme Mew - in an attempt to bring all sides together.
But Premiership Rugby and LNR are forging ahead with their own plans, having also extended an invitation to Celtic and Italian teams to join them.