Work and Pensions Secretary Damian Green has admitted a small number of people could have their benefits cut due to controversial changes to Personal Independence Payments (PIP).
Mr Green said there may be "a handful of people" who have been awarded higher levels of PIP as a result of the regulations, which the Government is looking to overturn.
This is because their cases went through the tribunal process in the period between the changes being introduced and ministers reversing them, said Mr Green.
The Department for Work and Pensions (DWP) would not look to claim this money back, Mr Green added, though he suggested the amount of money the claimant received through PIP would be cut once they were reassessed.
The admission was coaxed out of the Work and Pensions Secretary by Labour MP Kate Green, amid calls to guarantee that no claimants will see their benefits cut as a result of the decision.
Ms Green, a former shadow work and pensions minister, said: "May I understand exactly something the Secretary of State said a few moments ago, when he said nobody would face a cut in their benefit?
"Did I understand him correctly to say that while they would not see their initial DWP benefit award cut as a result of these regulations, where that benefit had been increased by a tribunal and these regulations now supersede the judgment of that tribunal, they could see their benefit reduced back to the original award level?"
Mr Green replied: "That's indeed what I said.
"We think there may be a handful of people whose appeals have gone through the courts in this very, very small period.
"That money will not be clawed back from them, that's what I said earlier on."
Earlier, Mr Green had hinted that such claimants could see their benefits reduced when they were reassessed.
He said: "I can only repeat what I have said before and what my honourable friend (Ms Mordaunt) said, that no claimant will see a reduction in the amount of benefit they were previously awarded by the DWP.
"The committee says there may have been some people who may have seen the award lifted by a tribunal and it is indeed possible that will have happened.
"We will, of course, not be claiming back money these individuals have received during the period before the new regulations come into force.
"Nobody will get any reduction from what they were awarded from the DWP, which is what I have said all along.
"Reassessment, as you know, happens regularly under PIP and other benefits."
The Government moved to tighten the scope of PIP after a tribunal said claimants with psychological problems who cannot travel without help must be treated like those who are blind, and those who need support to take medication should be assessed the same way as those managing therapies like dialysis at home.
Ministers have insisted the changes are needed to restore Parliament's original intention on who should receive PIP.
But the Social Security Advisory Committee, which advises the Government on welfare issues, recently wrote a letter to ministers outlining concerns that the changes could present "unintended operational and legal consequences".
Raising the issue as an urgent question in the Commons, shadow work and pensions secretary Debbie Abrahams said: "This directly contradicts comments made by the Prime Minister and the minister for disabled people (Penny Mordaunt) who stated no-one would see a reduction in their PIP award.
"Will the Secretary of State take this opportunity to correct the record?
"Will you guarantee that this will not be the case for claimants when they come for reassessment?"
Mr Green faced criticism from a number of MPs about the PIP system, as they raised the plight of individual cases who had been turned down for the benefit.
There were also concerns about how those with mental health conditions were treated during their assessments for PIP, as well as Motability vehicles being taken away from some people.
Labour MP Frank Field, chairman of the Work and Pensions select committee, said: "Despite what the Secretary of State says about the current benefit favouring those who do not have physical disabilities, the evidence coming to the select committee, who are inquiring into PIP, shows that those with other disadvantages find it difficult to qualify."
Mr Green said PIP was a vast improvement on the old Disability Living Allowance (DLA), with many more people with mental health conditions awarded higher rates of PIP.