Social care is facing a funding gap of more than £1bn by 2014 in England - a situation which would have consequences for the NHS, a leading think-tank says.
The King's Fund analysis predicted councils would struggle to protect home help and care home places as they come to terms with funding cuts.
The report said if this happened there could be more admissions to hospital and longer delays in discharging.
But the government said it did not believe there would be a funding gap.
The Department of Health has earmarked more money for social care.
By 2014 there will be an extra £1bn made available to local authorities from the NHS budget. The Department of Health allocations to councils are also rising.
However, local authorities also rely on funding from other government departments, which will be cut by 27% over the next four years, as well as the money they can raise from council tax to pay for social care.