The Conservatives stand accused of abandoning their outright opposition to Labour's 'death tax' proposals for funding social care.
Terms of reference for the independent commission tasked with probing the future of Britain's care services for the elderly were open-ended.
It means the commission on the funding of care and support, to be chaired by Andrew Dilnot, will be free to consider other options including compulsory schemes.
The Labour government had proposed a £20,000 inheritance tax to pay for then-prime minister Gordon Brown's enhanced domiciliary care proposals.
Andrew Lansley responded by attacking what he called Labour's 'death tax' and refusing to attend cross-party talks on the issue if the compulsory option remained off the table.
"He even produced crass posters with gravestones to make his point," shadow health secretary Andy Burnham said.
"Now he is giving this commission free reign to look at compulsory options. He needs to explain today what has happened to change his thinking."
Mr Lansley avoided commenting on the issue beyond warning that the number of 85-year-olds is projected to double by 2026.
"We must develop a funding system for adult care and support that offers choice, is fair, provides value for money and is sustainable for the public finances in the long term," he said.
Liberal Democrat care services minister Paul Burstow indicated the coalition government was prepared to compromise, however.
"For too long social care reform has been a talking shop," he said.
"Trade-offs will have to be made but we are determined to build a funding system that is fair, affordable and sustainable."
The government hopes to put legislation in front of parliament next year.