A partnership of 50 voluntary organisations, supported by former Conservative leader Iain Duncan Smith, has accused Waltham Forest Council of excluding voluntary organisations from commissioning processes, delaying crucial funding decisions and failing to consult.
WellComm, which represents health and social care charities, said that it was speaking out after the council, controlled by a Labour and Liberal Democrat coalition, had ignored its attempts to meet to discuss core funding.
Sheena Dunbar, chief executive of Age Concern Waltham Forest, which runs WellComm, said charities were frustrated and demoralised.
"Three years ago we worked in close collaboration with the council," said Dunbar. "Now the whole thing has totally broken down."
Two local MPs have backed WellComm. Duncan Smith, MP for Chingford and Woodford Green, said he was concerned that the council was jeopardising charity-run services.
"The council has shown a disregard for the needs of the voluntary sector in failing to consult adequately, in numerous delays through planning and implementation foul-ups and in imposing extra and unnecessary costs through an ill-thought-out commissioning process," he said.
Harry Cohen, Labour MP for Leyton and Wanstead, said there had been a serious breakdown of the relationship. He said: "The voluntary sector must not be placed in a position where it cannot access resources or work effectively for local people."
Councillor Liz Phillips, cabinet member for health, adults and older people at the council, said: "We are disappointed WellComm feels this way because we work very hard to communicate effectively with it."