Warwickshire County Council has reduced its voluntary sector spending by £609,000 in another week of council cuts across England.
Charities delivering adult health and community services will be worst affected as the county seeks savings of £13m.
"Everyone knows they have to make economies, but the voluntary sector is a soft target," said Trevor Russel, marketing and communications manager at Stratford-on-Avon District Council for Voluntary Service.
He accused the council of not consulting adequately. However, Mark Beach, chair of Warwickshire Community and Voluntary Action, said it had been "well consulted".
A council statement said it had "done its best to limit the impact of savings requirements on the third sector" and pledged to conduct an internal review of all voluntary sector funding.
Elsewhere, Forest of Dean District Council plans to cut its voluntary sector budget by 10 per cent to £223,000.
Tim Fretter, director of Forest Voluntary Action Forum, questioned whether consultation had been Compact-compliant. The forum has sent a letter to councillors demanding that "any decisions are based on a clear understanding of the role of the sector".
The London borough of Merton has reduced its budget for infrastructure organisations by £70,000 - a 10 per cent cut.
The brunt of the cuts will be felt by two groups, the Ethnic Minority Centre and Merton Racial Equality Partnership, because a grants panel said they did not show "value for money".
There was better news in Newcastle, where the city council decided to maintain its voluntary sector budget, despite a £20m shortfall.