The chief executive responsible for Stoke Mandeville hospital told a local MP in 2012 that Jimmy Savile was "not given free access" to clinical areas, the BBC has learnt.
Savile abused more than 60 people on the hospital site including wards where young children were treated.
Reading East MP Rob Wilson said Anne Eden's comments to him were "bordering on misleading".
Buckinghamshire Healthcare NHS Trust declined to comment.
The MP's complaint follows the publication on Thursday of the report of an independent investigation into Savile's behaviour at the hospital.
It found that he had "virtually unrestricted access" to clinical areas and patients during the 1970s and 80s.
'Not full truth'
It also revealed that Savile was given a bedroom that allowed him to live "alongside young female students for four decades".
Following the emergence in September 2012 of the allegations about Jimmy Savile's abuse at Stoke Mandeville, Reading East MP Rob Wilson wrote to the Chief Executive of Buckinghamshire Healthcare NHS Trust to express his constituents' concerns about the claims.
Anne Eden sought to reassure him about Savile's freedoms at the hospital in an email sent on 12 October 2012, and obtained by the BBC through a Freedom of Information request.
"There has been a lot of conjecture in the media regarding Jimmy's access at Stoke Mandeville", she wrote. "I would like to clarify that he was not given free access around our clinical areas.
"To the best of my knowledge, whenever he attended the hospital, he would give advance notice and usually be in attendance with his fundraising team. He and his team were given access to a room, but this was not within the main hospital nor in any clinical area."
Mr Wilson said: "It is extremely disappointing that the answers I got at the time were inadequate and unfortunately wrong.
"I felt at the time I was corresponding with Ms Eden, that I was not getting to the full truth. There were clearly media reports suggesting that he had more access than she was telling me.
"I was very surprised to receive the first letter suggesting that he had no unsupervised access and suggesting there wasn't any great need to look further."
He said he understood that the email was written at a difficult time for the hospital but "it was a very important issue where the truth - more than anything else - had to come out".
Meanwhile, a fomer cabinet minister who agreed a deal with Savile under which the late DJ would fundraise for the hospital on condition it was kept open, has told the BBC he accepts a share of responsibility for enabling Savile to abuse patients.
On BBC Newsnight, Lord Jenkin - who was social services secretary between 1979 and 1981 - said: "I deeply regret what we now know Jimmy Savile got up to in this hospital."
He told the programme he was not aware at the time that Savile was a sexual predator who had been given the freedom of the hospital.
"I have been appalled to read just how far he had gained access," he said.
When asked if he should have known about the level of freedom Savile had at Stoke Mandeville, he replied: "Maybe I should have, but I didn't."
Thursday's report said that Savile had abused 63 people connected to the hospital and that one formal complaint about him - made by the father of an 11-year-old girl - was ignored.
It said his reputation as a "sex pest" was an "open secret" among some staff but that allegations about his behaviour probably did not reach managers.
According to the report, Savile's victims, aged between eight and 40, were abused over a 24-year period between 1968 and 1992.
Sexual abuse by Savile ranged from inappropriate touching to rape - including the rape of children under the age of 12.