One in three English councils faces cuts in Government support next year putting more pressure on social care budgets, Labour's Andy Burnham has said.
The former health secretary called on Prime Minister Theresa May to intervene as local authorities look set to lose out by £40 million.
Mr Burnham said the figures show the Government has "misled" people over extra funding for social care.
Changes will see London's Tower Hamlets losing £3.4 million, while Salford faces cuts of £2.3 million, according to Mr Burnham.
The ex-cabinet minister, who is seeking to become mayor of Greater Manchester, warned that 57 of 157 local authorities that provide social care in England will lose a combined £40 million.
Mr Burnham said Government moves to divert funds from the New Home Bonus scheme to one-off social care grants in 2017/18 will see many councils worse off.
The ex-minister said Birmingham would lose out by £1.3 million as the city will be among those receiving less from the new grant than the housing scheme - despite Government assurances that the authority would benefit from the changes.
Mr Burnham said: "Theresa May's Government are playing a dangerous game on social care. They promised help for struggling councils but it is now clear that, while they were giving with one hand, they were taking away with the other.
"Far from acting on the social care crisis, the brutal reality is that the Government is deepening it and inflicting even more cuts on councils in some of the poorest parts of England.
"Social care has already been cut to the bone. If this further round of cuts goes ahead, it could have serious consequences for the NHS.
"That is why I am calling on Theresa May to intervene in this row and give a clear guarantee that no council in England will face cuts in central Government funding next April."
A Government spokesman said: "The Government announced earlier this month almost £900 million of additional funding over the next two years to tackle the growing pressures on social care.
"However, we know that money alone is not the solution. There is a diversity of provision across councils, with many already providing high-quality social care services within existing budgets.
"The Prime Minister is clear that we need to find a long-term sustainable solution, including making sure all local authorities learn from the best performers to raise standards across the whole system."
A Conservative spokesman said: "It's disappointing that Andy Burnham has chosen to play politics on this issue. Particularly so given Labour's record. They ran for election in 2015 explicitly ruling out any additional money for social care - and Andy Burnham himself was shadow health secretary at the time. Now they're promising money which they've already allocated many times over elsewhere.
"It's this Conservative Government which is taking the necessary steps to protect social care. We recently announced additional money for councils in the short-term. And we've been clear that in the long-term we need deeper reforms that go beyond simply how much money is spent - to ensure social care is put on a sustainable footing the years to come."