A meeting between the Welsh Rugby Union and the regions has ended with no deal being agreed but further talks planned.
Funding, the exodus of Welsh players and an Anglo-Welsh league were issues discussed at the meeting.
A WRU statement said it was "hopeful" the participation agreement between the parties would be signed.
"We have to continue our dialogue and we have to continue talking," said Cardiff Blues chairman Peter Thomas.
"We continue to try and take it forward in the best interests of Welsh rugby.
"The mood [of the meeting] was good and everybody was acting in a very responsible manner.
"We are very mindful of the difficulties we are all facing - from a player, a sustainable business and a competition point of view.
"We try as a responsible body to try and find a solution and we will continue to do that."
The WRU statement released after the meeting at the Liberty Stadium in Swansea on Wednesday read: "At the meeting of the Professional Regional Game Board today between the Welsh Rugby Union and the four Regional Organisations a range of topics were discussed.
"At this key moment for rugby in Wales the WRU continues to work hard in the best interests of Welsh rugby as a whole.
"It would be unfair on the fans, the players and all of Welsh rugby to make any further speculative comment at this time.
"However, the WRU remains hopeful that the Regions will decide to continue with the Participation Agreement by the deadline of 31st December 2013."
The regions have until the end of the month to sign a new agreement or face losing funding of up to £16.5m a year.
The regions are also considering whether to break away from the WRU and play in a new Anglo-Welsh league next season.
Representatives from Welsh rugby's four regions met the WRU in an attempt to resolve their differences.
Ospreys, Blues, Scarlets and Dragons say they want to play against English clubs rather than be forced by the WRU to compete in the Heineken Cup.
The regions could take legal action for the right to play in cross-border tournaments without WRU permission.
As they gathered at the Ospreys' home, Swansea's Liberty Stadium, there was increasing speculation the regions will not sign a participation agreement with the union before the 31 December deadline.
The regions had been keen to increase revenue by joining the proposed new Rugby Champions Cup, a 20-club tournament proposed by English and French sides.
But those plans came to nothing as the home unions, England aside, committed to the current Heineken Cup.
Last week the English clubs confirmed they would not be involved in the competition next year.
Rugby Football Union chief executive Ian Ritchie is still confident English sides will compete in Europe next season, insisting there is still "a deal to be done".
WRU chief executive Roger Lewis has said the union is committed to the supporting the regions.
The WRU has offered to help the four regions keep their leading Welsh players in Wales, and has said it would employ all of their leading Wales internationals whose deals expire in 2014.
The current uncertainty over European competition has led to a host of star names considering their playing futures beyond the end of the 2013-14 campaign.
Wales captain Sam Warburton has given Cardiff Blues and the WRU a Wednesday deadline to put together a deal to keep him in the country.
One of players who has already decided to leave Wales at the end of the season is Scarlets centre Jonathan Davies, who has signed for French side Clermont.