Plans to form a cross-party commission on the future of the NHS in Wales have been axed.
The decision came after Plaid Cymru announced it would not take part, following on from the Conservatives who previously pulled out.
The commission was meant to be a place for the parties to freely debate the future of the NHS.
Leader of the Welsh Liberal Democrats Kirsty Williams said the collapse would leave patients in Wales disappointed.
But in a heated exchange, the Welsh Tory leader Andrew RT Davies criticised the whole process.
Plans for a commission were revealed in February, when the Welsh Health Minister Mark Drakeford wrote to the Lib Dem leader setting out an agreement in principle.
Confirming the offer of a commission at the time, Mr Drakeford said: "Discussions about the long-term future of the Welsh NHS should sit outside the knockabout of day-to-day party politics."
The proposal would have seen a year-long cross-party investigation into how the NHS in Wales could be improved.
It was due to convene in April.
Plaid Cymru health spokeswoman Elin Jones said the timing of the commission was not right given the recent political rows involving the NHS and the forthcoming elections.
"Election time is not the time to be discussing impartially the future of the NHS," she said.
"Fundamentally, it was a commission that was going to be confined by party politics rather than released from the interference of political parties."
Mr Davies said his party had been forced to reject the plans because the terms of reference for the commission had already been set out.
"So no discussion around the terms of reference, the reporting lines agreed," he told BBC Radio Wales.
"If you want an all-party group to have genuine consensus and the ideas are valued equally, then you do have to get people on board at the outset."
Mr Davies accused the Liberal Democrats of jumping the gun by going public on proposals for a commission.
"Frankly, they were just trying ahead of the general election to take some PR out of a very serious issue," he claimed.
But Ms Williams rejected the accusations, and told the Tory leader he was "taking his toys home" because of the delay in receiving the invitation to take part.
"If the Tories and Plaid Cymru are serious about trying to improve the health service for the patients in Wales and the staff that work in it, they could still - even at this stage - say 'we want to be a part of this'," said the Liberal Democrat leader.
"This was an opportunity for all political parties to bring their ideas and their solutions, and more importantly than that, to hear from clinicians and patient representatives, to work together."
Labour's deputy health minister Vaughan Gething told the Wales Report programme he regretted that the all-party commission would not be taking place.
"It's disappointing that there hasn't been an agreement - it could only take place if at least three parties take part - they've chosen not to," he said.
"It was an honest attempt by the Welsh government to get people into a position where they can talk about the serious challenges facing the NHS".
Analysis by BBC Wales political editor Nick Servini
The Welsh government had already priced in a refusal to take part in the commission by the Conservatives but still felt it could have gone ahead.
The rejection by Plaid is a game-changer and means that any attempt to get cross-party consensus on the future of health service this side of the next assembly elections will be abandoned.
Ironically, the idea of the commission was to find consensus and take the heat out of the debate. The opposite has happened.
Plaid are saying now is the wrong time. Behind the scenes they are also unhappy with the way the story over talks between the Lib Dems and the Welsh government was broken on BBC Wales.
Meanwhile, the Lib Dems have accused Plaid of putting politics before patients. And the Welsh government have blamed the Lib Dems.
The upshot is that any kind of cross-party consensus on the future of the NHS is now not going to happen this side of the next Assembly elections.
The head of the Royal College of Nursing in Wales, Tina Donnelly, has been outspoken on the issue of politics and the NHS in Wales.
Speaking on Wednesday, she said she believed a NHS Commission should still go ahead.
"We have been quite vocal about the need to rise above the political issues that normally ensue in party politics because the Welsh NHS is vitally important to the population of Wales," she argued.
"Let's be clear. If we were looking at the defence of the country, on a UK basis we have a cross-party agreement where people come together to determine the amount of resource and how we might go to defend our nation.
"That is no different in our book in determining the finances and the need to deliver a health service that is conducive to enhancing the wellbeing of the Welsh population
"To us as a college then we do feel very strongly that the politicians should actually put party politics behind them and come together and have this commission."