David Cameron faces a battle with Cabinet colleagues over the future of pensioner benefits as the Conservatives start to draw up their manifesto for the 2015 general election.
The Prime Minister promised a Tory government would protect the basic state pension from cuts until at least 2020 by retaining the "triple lock" guarantee.
But his failure to rule out a squeeze on other pensioner benefits raised speculation that perks such as winter fuel payments, free bus passes and TV licences could be stripped from better-off OAPs.
A Downing Street source insisted, however, that he remained "attracted" to the idea of repeating a 2010 election pledge to shield them from austerity measures.
With wealthy pensioners benefiting while millions of other welfare recipients face dramatic cuts in state help, Mr Cameron has been under mounting pressure to abandon the promise.
Chancellor George Osborne has said the post-2015 affordability of the payouts must be examined and Work and Pensions Secretary Iain Duncan Smith is said to be among others pushing for change.
Labour has said it would strip winter fuel payments from the richest 5% of pensioners and the Liberal Democrats would means-test the benefits.
A Number 10 source made clear that did not signal an abandonment of the previous policy.
"The PM has kept his promise for this Parliament. He is attracted to repeating it for the next Parliament," the source said.
"But the next manifesto is still over a year away and no final decisions have yet been taken."
In new year media interviews, Mr Cameron sought to seize the political initiative by reassuring OAPs over continued rises in the basic state pension.
Under the "triple lock" the basic state pension rises in line with inflation, wages or 2.5% - whichever is the highest.
He said that it was right to prioritise "dignity and security" for people in their old age while austerity continued to bite into welfare and other spending.
The protection had been made possible by "difficult decisions" such as extending the retirement age, meaning millions in their 30s and 40s will wait longer to get a pension, he said.
He denied the move was designed the win the support of the over-60s, who are far more likely to vote than younger people.
Labour leader Ed Miliband said the Opposition would hold back from making tax and spending commitments until it published its election manifesto.
"But nobody should be in any doubt about our commitment to the triple lock," he added.
Deputy Commons Leader Tom Brake indicated that he expected the Liberal Democrats to match the extension of the guarantee - which was originally in the party's 2010 manifesto.
Mr Cameron has already indicated that the state pension would be the only spending exempt from a new cap on overall welfare spending.
Labour had excluded it from any cap "in the short term", Mr Miliband said.
"Obviously in the longer term we've got to keep an eye on these things - the long-term forecasts for pensions."