Jeremy Hunt has stepped up pressure on NHS bosses to end the use of legal gags on whistleblowers but faces calls for an independent inquiry into his own department's involvement.
In a letter to the chairmen of every Trust, the Health Secretary warned against a culture in some quarters of "institutional self defence that prevents honest acknowledgement of failure".
In order to avoid a repeat of the Mid-Staffordshire scandal it was vital to "recognise and celebrate staff" who had the "courage and professional integrity" to speak out over safety concerns, he suggested.
He called on all bodies to ensure their actions met both the letter and the spirit of NHS whistleblower guidance.
Mr Hunt warned United Lincolnshire Hospitals Trust that it faced action if it had wrongly tried to silence a former chief executive from speaking out about patient safety concerns as part of a unfair dismissal case settlement.
Gary Walker was threatened with legal action related to his reported £500,000 payout after breaking his silence to allege he was forced out of his job in 2010 because he put patient safety ahead of Whitehall targets.
The trust is one of 14 being investigated by health chiefs over high mortality rates in the wake of the public inquiry report into serious failures at Mid Staffordshire NHS Foundation Trust that led to hundreds of unnecessary deaths.
Mr Walker welcomed the Health Secretary's intervention as a "very positive move" but said the threat of action against him for an interview with the BBC's Today programme on Thursday had still not been lifted. And he suggested that Whitehall had a hand in prompting the action and should also be investigated.
"The threat against me has still not been withdrawn, despite the reassurance that it should not be in place," he said in his latest interview with the programme.
"I don't think I want to be too negative about Mr Hunt. He has clearly taken a personal interest and said that he will personally carry out the investigation and get to the bottom of it."