At least 25,000 council jobs in England will be under threat in the next three to five years.
The forecast is based on answers from 49 councils with a combined workforce of 256,000, suggesting cuts of 10%.
Services such as libraries and nurseries face cuts as councils grapple with the impact of the recession.
Responding to the survey, PM Gordon Brown insisted that, while there was a need for efficiency savings, there was no need for cuts to services.
One expert said the number of job losses could reach 100,000, while one union warned of “social disharmony”.

Councils across the UK say jobs and services will have to be cut if, as they expect, funding from central government is reduced.
More than 70% of councils in England that responded to the survey predicted spending cuts of between 5% and 20%.
Roads, libraries, the arts and leisure appear most at risk of cutbacks. Children’s social services, services for the homeless and planning appear to be safest.
The Local Government Association, which represents English and Welsh local authorities, said town halls had been battling the effects of recession for more than a year.
Sources of income have dropped sharply at a time when more and more people are turning to councils to help them through tough times.

Low interest rates mean councils are much less able to rely on their savings, plummeting house and land prices have hit hard and income from leisure centres and a range of other services has fallen.
She said tough decisions would have to be taken, but “councils will do everything they can” to protect front-line services.
But eight authorities – Kirklees, Leeds, City of Bradford, Sheffield, Stoke-on-Trent, Nottinghamshire, Lincolnshire and Surrey – said 1,000 or more posts might be lost within five years.
Birmingham City Council, is planning savings of £69m in the next financial year, which could mean the loss of up to 2,000 jobs.
Shropshire Council has also said it is planning to cut more than 1,000 posts over the coming years.