Former health secretary Alan Johnson ordered figures for the potential number of avoidable deaths at Stafford Hospital to be taken out of a report.
A public inquiry is taking place into failings at the hospital after a higher than expected number of deaths between 2005 and 2008.
In a statement Mr Johnson said there had been no reliable evidence about the exact number of deaths at that time.
The inquiry is looking into monitoring by regulatory bodies.
Mr Johnson's stance has received the backing of Bill Moyes, the former chairman of the independent NHS foundation trusts' regulator, Monitor.
'Distress to families'
My Moyes said he recalled an extrapolation for the potential number of avoidable deaths at the trust being somewhere between 400 and 1,400 when the actual figure was subsequently found to be 1,200.
"This estimate to be included in the report was based on simple arithmetic multiplying the standardised mortality rate for the trust by the number of patients it had treated rather than an analysis of individual cases and I believe it was inappropriate to include such a calculation in the report," he said.
The inquiry has been told of a meeting in March 2009 which included Mr Johnson, Mr Moyes and the then chairman of the Health Care Commission, Sir Ian Kennedy.
Mr Moyes spoke of an argument ensuing when Mr Johnson insisted the final report should not contain estimated figures and the HCC was then instructed to leave them out.
In a statement Mr Johnson said: "At the time in question there was no reliable evidence about the exact number of avoidable deaths at Stafford Hospital.
"I was not prepared to release estimated figures into the public domain as these were not supported by robust clinical evidence as Mr Moyes makes clear."
To have done so, he said would have caused unnecessary suffering and distress to the families of patients who had unavoidably died at the hospital.
After the day's hearing had finished, Julie Bailey of Cure the NHS, a group which campaigned for the public inquiry, said the news the figures had been ordered to be removed came as "no surprise".
"None of the ministers wanted to embarrass themselves - it was on their watch that hundreds of people died," she said.
"These figures were backed up by the Health Care Commission's own statistics on mortality but there is no way now we will find out how many lost their lives unnecessarily," she said.
"But does it really matter whether it was 400 or 1,200? There were unnecessary deaths at Stafford Hospital."
A Healthcare Commission report, issued in 2009, listed a catalogue of failings at the hospital including receptionists assessing patients arriving at A&E, a shortage of nurses and senior doctors and pressure on staff to meet targets.
Two earlier inquiries into the report were heard in private.
The inquiry is continuing.