"Gagging clauses" which stop NHS staff from speaking out about their concerns should also be scrapped, said Roger Lyons, general secretary of the technical union MSF.
He told the Nolan committee that appointments to NHS bodies should be politically balanced and responsibility for them should be taken away from the Government.
His union's report to the committee said many health service staff were concerned at the effects on patient care of the new, sometimes "excessively vigorous" commercial ethos in the NHS.
"It is no exaggeration to say that a climate of fear now exists within the NHS, and this has given rise to considerable staff concern about the issue of freedom of speech," the report said.
The only way to tackle excessive secrecy was to introduce an independent element, with staff able to take concerns beyond management, perhaps to the health service ombudsman.
Mr Lyons said he had personal experience of the effects of total party domination of a public body. He was dropped from a school governing body when the Tory council in Barnet, north London, removed every Labour-nominated governor from every school in the borough.
A new Labour majority last year brought the restoration of political balance, he said.
Union research had also uncovered the fact that in Labour-controlled Ealing in west London, all four main NHS bodies were headed by Conservatives.
The union called for an NHS "charter of staff values" which would give staff the duty to report their concerns about the running of the organisation.
Labour MP Dale Campbell-Savours, a long-standing critic of MPs being allowed to accept paid lobbying work and other private interests, urged the appointment of an ethics registrar for Parliament.
The registrar would investigate complaints about MPs and ministers and would report to Parliament and, if necessary, the Prime Minister.
"The public want to be assured that standards of propriety are being maintained," he said. "It is important for the public to know that the registrar can't be fixed."
The Nolan committee should also consider whether the interests of MPs' spouses should be registered in some cases, he added.
A Conservative MP Iain Duncan-Smith said he believed some of the problems surrounding MPs' interests could be solved by "complete and utter disclosure".
On quango membership, he said: "Why not build on what we have already got? If it is a concern that there are too many people appointed to these bodies, why not have one of these people elected, perhaps the chairman, so they would be accountable to their local community?"Reuse content