The leader of Derbyshire County Council has said a health organisation's proposal to cease all £1.1m funding for charities "puts the whole voluntary sector at risk".
Barry Lewis spoke out after NHS Derbyshire Clinical Commissioning Groups put forward plans last month to plug an £80m gap between funding received for services and the cost of providing them.
Charities were given just three weeks to respond to a consultation on the plans, which could affect dozens of healthcare organisations in the county.
In a letter to Dr Chris Clayton, chief executive of the CCG, Lewis said he was "surprised and dismayed" to be informed of the cuts by South Derbyshire CVS. The CVS itself is set to lose £170,000 – about a third of its funding.
He wrote: "Firstly I am amazed that you have not had the courtesy to advise me, as leader of a key partnership organisation, of your intentions.
"Secondly, as we jointly fund these organisations, I am wondering if you have fully considered the impact of your individual decisions on the system.
"The decision by the combined CCGs to remove this level of infrastructure funding puts the whole voluntary sector at risk.
"This funding enables these organisations to support and train an army of volunteers and to bid for millions of pounds of external funding into the Derbyshire system."
Lewis accused the CCG, which consists of four NHS commissioning bodies, of "making poor decisions whilst flying blind" and said he would have "no hesitation in escalating my concerns with both local MPs and central government" if the CCG did not reconsider and "start to engage in intelligent conversations".
South Derbyshire CVS deliberately did not respond to the CCG's impact assessment paper, which was sent as part of the consultation, on the grounds that three weeks is insufficient time to engage. It wants a 12-week consultation.
"The CCG has a duty to conduct a proper due process and I'm not sure it has," said Michelle Skinner, chief executive of South Derbyshire CVS, who did not rule out legally challenging the process.
Skinner met CCG representatives yesterday to discuss the cuts. She described the talks as "more positive" than previous discussions but fears the CCG will still ratify the proposal this month and then give three months notice of withdrawal of funding.
"It would seriously affect the long-term viability of the sector," she said.
Almost 300 organisations responded to a survey on the cuts run by the CVS, which is using the Twitter hashtag #CVSSOS to highlight the issue.
Clayton was due to meet the council's cabinet members for health and communities and adult care on Thursday to discuss the cuts.
Third Sector asked the council and the CCG what the meeting had achieved.
A council spokesman said: "I can confirm that discussions will continue."
A CCG spokesman said a decision on the proposed cuts was due to take place on 17 August and it was considering responses to the consultation. He was unable to discuss matters further.