Spending on adult social care is to be slashed by around £1bn this year as councils struggle to cope with budget cuts at a time of increased need, new figures show.

The scale of the shortfall was laid out in a survey for the Association of Directors of Adult Social Services - which was completed by 98 per cent of local authorities involved.

Around a quarter will have to come from reduced services despite efforts to find more efficient ways of operating to spare the frontline, the professional body warned.

According to the survey, people assessed to have “moderate” or “low” need will get free help only if they live in 26 of 148 council areas - down from 41 last year.

Ministers allocated an extra £1bn from Department of Health funding to help meet growing demand but that money was not ring-fenced so does not automatically protect care from efficiency measures.

An extra £425m is needed just to deal with the impact of an ageing population and a “very significant increase in the numbers of people with learning disabilities needing substantial levels of support”, ADASS said.

Plans are in place to absorb around 70 per cent of the £1bn reduction in efficiency and redesigned services - including integrating with the NHS and better involving independent and voluntary providers.

ADASS said it was trying to co-ordinate action across the country to minimise the impact on services and noted that councils had spared social care some of the drastic cutbacks seen in other areas.

But it added: “Councils will do everything they can to reduce the need to spend on long-term care through advice, information, prevention and reablement and by ensuring that value for money is achieved.

“However, this year’s savings targets in councils are just the beginning of a three to four year programme of reductions, demographic pressures will not abate and councils’ ability to find alternatives to service reductions will inevitably reduce over time.”

The future for provision is being examined by the Commission on the Funding of Care and Support, chaired by Andrew Dilnot, which is due to report its findings to the government in July.

Mr Dilnot said there was “no doubt that there is a growing amount of unmet need”.

“We are in the strange position where the spending review allocated extra money but because the local authority as a whole is so tight, there is no doubt that there is a reduction in the amount of money that’s getting through to social care,” he told BBC Radio 4’s Today programme.

Care services minister Paul Burstow said: “The government is putting an extra £2bn into supporting social care by 2014 and there is an unprecedented transfer of cash support from the NHS to social care.

“This funding, together with an ambitious programme of efficiency, should enable local authorities to protect people’s access to services and deliver new approaches to improve their care.”