The cost of capping social care bills for the elderly will have to be considered "carefully" against other public spending priorities, Health Secretary Andrew Lansley has warned.
An eagerly-anticipated review commissioned by ministers called for the state to cover costs when they rise above £35,000 for any individual.
The Commission on Funding of Care and Support also urged an increase in the means-tested assets threshold from £23,250 to £100,000 for those in residential care.
Mr Lansley promised to bring forward Government plans for adult social care reform in a White Paper next spring, but indicated that the £1.7 billion price tag would require "trade-offs".
"In the current public spending environment we have to consider carefully the additional cost to the taxpayer of the commission's proposals against other funding priorities," he said.
While seeking to address the costs of care, the commission's proposals also included charging elderly people in residential accommodation for living costs such as food and accommodation. This would be capped at between £7,000 and £10,000 a year.
It also indicated that the cap on lifetime contributions to social care costs could be set at between £25,000 and £50,000, although it added that £35,000 was "the most appropriate and fair figure".
Mr Lansley said that this range of options "could help us to manage the system and its costs".
The commission, chaired by economist Andrew Dilnot, suggested that pensioners should pay extra tax to help cover the cost of the proposals, although it was unclear what form that might take.
Raising the prospect of a "specific tax increase", the commission said it would "make sense for this to be paid at least in part by those who are benefiting directly from the reforms".