Health Secretary Andrew Lansley has ordered a review into the hospitals regulator's handling of criticism of its management.
Kay Sheldon, a member of the board of the under-fire Care Quality Commission (CQC), has said she raised concerns about chief executive Cynthia Bower, only for them to be dismissed.
She accused Ms Bower and CQC chairwoman Dame Jo Williams of putting "reputation-management and personal survival" ahead of patients' best interests.
Ms Sheldon spoke out at a public inquiry into hundreds of deaths at Stafford Hospital during a period when Dame Jo was responsible for its oversight.
"A few months ago, I again raised the issue of whether Cynthia Bower's position was tenable. The response I got was that 'we do not need a high-profile sacking at this time'," she said in written evidence to the inquiry.
Mr Lansley has appointed Gill Rider, president of the Chartered Institute of Personnel and Development and a former Cabinet Office civil servant, to investigate the claims.
The National Audit Office has recently criticised the CQC for not providing value for money and risking "unsafe or poor quality care".
The Department of Health said Ms Rider's review was distinct from a separate Performance and Capability Review of the CQC which is under way.
"We have ordered a review to quickly establish the facts around how Kay Sheldon's raising of concerns about the CQC were handled," a spokesman said.