The Welsh Rugby Union insisted it was working to avoid a crisis over the participation agreement after Regional Rugby Wales announced the governing body's proposal was "completely unacceptable" following "indescribably tortuous" negotiations.
The four regions which form RRW - the Blues, the Dragons, the Ospreys and the Scarlets - released a statement, saying every time progress was made "two steps back" followed.
The WRU responded, saying it was "saddened and surprised" by the RRW statement.
The WRU added in a statement: "The WRU will not respond to the highly emotional content of the document and assures all involved with Welsh rugby that the governing body will continue to work with complete focus on reaching agreement with the four regional organisations as soon as possible.
"The WRU remains determined to conclude an agreement which will ensure the existing four regional organisations continue as the nominated teams to take place in all IRB sanctioned competitions for the professional level of rugby involving teams from Wales."
The participation agreement, which ended on June 30, covers issues such as the competitions the teams play in, payment for international player release, overseas player quotas and the fourth autumn Test match.
No resolution to talks would throw into doubt the future of the regions and, potentially, professional rugby in Wales.
Wales captain Sam Warburton signed a central contract with the WRU which, at present, leaves him without a team to play for next season.
A RRW statement read: "Sadly, the Regions regret to confirm that despite an indescribably tortuous process of endless telephone calls and meetings since January 6, the control, commercial and financial conditions that are being demanded of them under drafts of the proposed new service agreement would be completely unacceptable for any responsible independent business to enter into and expose itself to.
"The regions have consistently made every possible effort to reach a positive and progressive agreement that truly works in the interests of both parties, to ensure a sustainable and competitive professional game in Wales at both regional and international level. They remain totally committed to the hope of reaching that solution.
"However, after many months of working hard to try to progress a new agreement, it is with heavy hearts that the boards of all four regions must now urgently consider the stark practical consequences of operating within a business model that does not include any form of agreement with the WRU outside IRB regulations and no WRU support or involvement in the development of professional regional rugby."
RRW stated public comments from leading figures in the WRU were not matched by actions in negotiations.
"Unfortunately, these comments in the public domain do not reflect the actual process that the regions continue to experience, with every apparent step forward eventually being replaced by two steps back," RRW said.
The WRU insisted it was following correct protocols in discussions.
The WRU added in its statement: "Following receipt of a copy of the draft RSA (Rugby Services Agreement) with marked comments by Regional Rugby Wales the WRU responded in writing on Thursday, July 10, with comments to the RRW amendments.
"This is the legitimate, proper and private method adopted within corporate governance for agreements to be negotiated and concluded.
"It is extremely unhelpful to the process for emotionally charged statements to be made, either verbally or in writing, to interfere with this process."
The WRU statement suggested it believes an agreement is close.
"The WRU urges RRW to continue to fully engage in this process and has been encouraged by some recent comments from senior RRW personnel confidently predicting a positive outcome soon," the statement added.
"The WRU is confident that the governing body and RRW are in substantial agreement on the total monies contributed by the WRU within the RSA and the governing body will work to ensure the rugby commitments associated to the payments are acceptable to all parties and in the best interests of Welsh rugby."