Councils could struggle to fund social care in the future, meaning services may be put at risk, leaders in the sector have warned.
George Osborne said social care could expect a cash boost through local authorities raising their council tax, as part of his Spending Review last month.
But the Care and Support Alliance (CSA) claims there is likely to be a real-terms cut in their funding.
After the Spending Review, the Institute for Fiscal Studies think tank warned that due to cuts of more than 50% in central government support over the five-year period for councils in England, their spending power will be more dependent on their ability to raise tax locally.
The Chancellor told MPs last month that £2 billion could be raised if all councils added 2% to council tax, and the money would be spent on adult social care.
He also said the Better Care Fund - which oversees integration between the NHS and social care - would have an extra £1.5 billion by 2019-20 for local authorities to access.
The president of the Association of Directors of Adult Social Services (ADASS) said councils could struggle, leading to a direct effect on their ability to provide care.
Ray James told the BBC: "Councils have tried to prioritise funding for social care ahead of other services. But its ability to do that seems to have come to an end, so I think we will struggle to put much more into social care.
"If that happens, services will be put at risk. We have an ageing population which is increasing demand and have to cope with the introduction of the national living wage.
"Without action, we will see care homes close and vulnerable people not getting care."
Vicky McDermott, chairwoman of the CSA, told BBC Breakfast: "There is just not enough money and it's not being funded quickly enough, so actually what we're likely to see next year is a real-terms cut in funding for those vulnerable people."
A letter has been sent to the Chancellor, signed by the ADASS, the Care Provider Alliance and the NHS Confederation.