Wales' four rugby regions are backing Anglo-French plans for a new European competition in a further threat to the future of the Heineken Cup.
Cardiff Blues, Ospreys, Scarlets and Newport Gwent Dragons claim the revamped tournament offers "significant advantages".
The Welsh Rugby Union opposes the new European competition.
WRU group chief executive Roger Lewis has said it would be a "crazy concept" to get rid of the Heineken Cup.
In a statement, Regional Rugby Wales, which represents the four Welsh regions, confirmed its full support for the proposed new Rugby Champions Cup competitions.
"Whilst there remain elements of detail to be confirmed, it is now clear that there are a number of significant advantages to the new competitions in equality of governance, format, qualification and distribution across the individual participating clubs," it read.
"Consequently, RRW looks forward to working with the WRU to support their efforts and positive engagement in striving to ensure our teams are involved in strong, valuable European clubs competitions in time for next season."
The Welsh, Scottish and Irish Rugby Unions are refusing to let their clubs participate in any European competition if it does not have the "full approval" of the International Rugby Board (IRB).
The IRB has previously indicated to the BBC it could support a new-look competition if it was approved by the English and French unions.
Europe's top teams currently compete in the Heineken Cup or second-tier Amlin Challenge Cup.
England's Aviva Premiership clubs and their French Top 14 counterparts announced in June 2012 their intention to leave the competition organised by European Rugby Cup Ltd (ERC).
ERC is staging a meeting for stakeholders in Dublin on Wednesday, but representatives of the English and French clubs are expected to boycott the gathering.
English and French clubs believe ERC has not made the most of commercial opportunities and that qualification for Europe is skewed in favour of Celtic and Italian teams.
Their contention that Pro12 teams have an unfair advantage when it comes to qualifying for European places has caused simmering resentment for several seasons.
At least three Wales teams automatically enter Europe's top tier no matter where they finish in the Pro12, while at least three of Ireland's four teams are also guaranteed entry. Scotland and Italy both get two spots.