Ministers face intense pressure to perform a U-turn over plans for a £1.3 billion a year cut in disability benefits as Tory MPs threaten to revolt over the measure.
Work and Pensions Secretary Iain Duncan Smith wrote to Tory MPs to insist that consultations were continuing while Cabinet colleague Nicky Morgan said the proposed cut was merely a "suggestion".
Chancellor George Osborne has been warned that the restrictions on the personal independence payment (PIP) would be defeated in a Commons vote as there would be enough Tory rebels to wipe out the Government's slender majority.
The squeeze on PIPs will see up to 640,000 people affected by tighter criteria, brought forward after a review by health professionals found people were being awarded points for aids and appliances already in homes or provided by the NHS and councils.
The Budget documents made clear that the proposals would save more than £4 billion by 2020-21.
Education Secretary Mrs Morgan appeared to indicate that the plans could be watered down in the face of a backbench revolt.
She told BBC1's Question Time: "This is a measure that is still being discussed in Government."
Mrs Morgan added: "It is something that has been put forward, there has been a review, there has been a suggestion, we are not ready to bring the legislation forward."
She insisted: "We want there to be control of the welfare budget. We also made it very clear that we are not going to balance the books on the back of the poor and the disabled and we absolutely hold to that promise."
Conservative backbencher Andrew Percy, who has organised a letter to Mr Osborne calling for a rethink, warned the Government would be defeated in the Commons if it tried to push the changes through.
Ministers insist that overall spending on disability benefits is going up and the changes are needed to make sure the cash is better targeted to those in most need.
But Mr Percy said it was clear the shift was aimed at hitting spending targets, not improving support, and that the Government was on course to suffer defeat in the Commons if it sought to push the change through.
He told Channel 4 News: "There is no measure that has been put before the House of Commons yet. If a measure is put before the House of Commons I think it is fair to say that it is unlikely to get the support of the House of Commons given how much concern there is on this matter.
"But this is a consultation, we are not there yet."
The Brigg and Goole MP wrote on Twitter: "If I can be honest, I'd rather have a penny or two on fuel if it protects PIP."
Conservative MP Johnny Mercer also expressed reservations about the plans, saying on Twitter: "Concerned by proposed changes to PIP. Not sure right direction."
Fellow Tory David Burrowes said the proposals were a "backward step" and urged ministers to "press pause on it".
He told BBC2's Newsnight: "There's lots that we are doing so much better but this puts us on the back foot."
Ministers are trying to win over MPs, stressing that the planned changes followed a consultation with disability organisations and the proposals were set out before the Budget.
Mr Osborne told the BBC he was "always happy to listen to proposals about how to improve on that".
"But we have got to control our disability budget and make sure help goes to the people who need it most."
In his letter, Mr Duncan Smith told MPs: "Last week, we published our response setting out our thoughts on how we should continue to take into account the use of aids and appliances.
"As the Chancellor said this morning, we will now take this response forward, continuing our discussions with disability groups and colleagues."
Justin Tomlinson, minister for disabled people, has been speaking to Tory colleagues to reassure them about the planned changes.
He told the BBC that although hundreds of thousands of people would be hit by the cut in 2020-21, many would not lose out completely: "A significant chunk of that 640,000 will continue to receive the benefit."