Community groups in rural mid Wales could close if a cash-strapped council axes grants, it has been claimed.
Powys County Council leaders are planning £12m of cuts and a 9.5% council tax hike to balance the books.
But Carl Cooper, chief executive of the Powys Association of Voluntary Organisations (PAVO), claimed there had been no assessment of the impact grant cuts would have on community life.
The council said: "There will be risk assessments with all budget lines."
The main source of grants for Powys charities and voluntary groups - the Community Enablement Support Fund - is due to be scrapped to save £133,000.
Grant aid for services such as tourism, arts, countryside and youth services is also set to be cut back.
Mr Cooper said the third sector in Powys involved about 60,000 volunteers and provided 3,500 paid jobs.
He said he "entirely sympathised" with the council but claimed short-term savings by cutting grants could put more pressure on statutory services such as social care.
"The loss of a grant to run a village community centre could result in the closure of the groups that use it, e.g. lunch club, youth club, community choir, yoga class," Mr Cooper told the Local Democracy Reporting Service.
"This could increase problems of loneliness and social isolation.
"Art and cultural groups could have projects that offer significant help for people living with dementia. If this finishes, what happens to them?
"This is why we've written to all councillors; we don't want them to make a decision without knowing the full facts."
In November, Powys council leaders backed plans to launch a local lottery to raise up to £60,000 a year for community groups it could no longer support with grant aid.