"Gagging clauses" in severance agreements for NHS staff in England must end, the health secretary says.
Jeremy Hunt told the Daily Mail said he wanted to see a clampdown on such practices and would seek to introduce wording into agreements making it clear people could still whistle-blow.
But fellow Tory MP Stephen Barclay has claimed the move may not go far enough in dealing with a lack of transparency.
The use of the clauses in the NHS is thought to have been widespread.
In the last five years, more than 400 compromise agreements outlining special severance payments for departing NHS staff have been approved by the Department of Health.
But the department has said it does not know the extent to which payments were tied to clauses stopping recipients speaking out about any problems of patient safety or care.
'Love the NHS'
Mr Hunt told the Mail a "culture of openness and transparency" was at the heart of trying to drive up NHS standards.
He said: "There has been a culture where people felt if you speak up about problems in the NHS you didn't love the NHS. Actually it's exactly the opposite.
'We are now saying we won't approve any [compromise agreements] with a confidentiality clause that prevents people speaking out about patient safety or patient care.
"We will make sure there is a specific clause in them saying that nothing in them can prevent people speaking out."
Mr Barclay, a member of the Commons public accounts committee, has sought to uncover how much public money has been spent on compromise agreements.
While welcoming the announcement, he told the BBC that other severance payments to staff made through a different process, known as judicial mediation, may not be covered by the new rules.
This process does not involve the Treasury or the Department of Health, Mr Barclay said.
He added: "The gagging clauses had a chilling effect. In essence it put the legal risk on the whistleblower to prove they were complying with the public interest disclosure act. That's really what led a lot of people to keep quiet.
"It is unclear whether payments made through judicial mediation will be covered by the announcement today.
"Parliament still doesn't know how much has been paid through judicial mediation and whether any changes will be made in terms of gagging clauses in those arrangements."
The move by Mr Hunt follows the scandal surrounding Stafford Hospital, where hundreds of patients are believed to have died after receiving poor care.
"Mid Staffs happened because there was a culture of covering up problems," Mr Hunt said.
"We need to encourage front-line NHS employees who see problems to come forward, in the first instance to tell their own institution about them, but then having the ability to go beyond that if they don't think anything is being done about their concerns."
In the wake of the Stafford Hospital scandal, the government has announced the creation of a new post of chief inspector of hospitals from autumn this year.
Mr Hunt said: "The chief inspector will examine lots of different areas, but one third of the entire score for a hospital will be based on patient experience - the extent to which patients would recommend your hospital to friends and family, the extent to which your complaints procedure actually listens to people.
"In too many places hospitals think that patient care is something you do when you have done everything else."
Fourteen trusts in England are currently being investigated for high death rates.
Controversy over gagging clauses has particularly focused on one of them, United Lincolnshire Hospitals Trust (ULHT), after its former chief executive, Gary Walker, broke a gag to speak about his 2010 dismissal and concerns over care.
In an exclusive interview with the BBC, Mr Walker - whose case was dealt with through judicial mediation - complained about "a culture of fear, a culture of oppression" within the NHS.
"These are big problems," he said. "And if you consider that the people that have been running the NHS have created that culture of fear, they need either to be held to account or new people need to be brought in to change that culture."