Officials are planning to review the historic D-notice system, which warns the media not to publish intelligence that might damage security, in the wake of the Guardian's stories about mass surveillance by the security services based on leaks from the US whistleblower Edward Snowden.

Sources said Jon Thompson, the permanent secretary of the Ministry of Defence, was setting up an inquiry into the future of the committee, raising fears that the voluntary censorship system also known as the DA-notice could be made compulsory.

The committee is supposed to be consulted when news organisations are considering publishing material relating to secret intelligence or the military. It is staffed by senior civil servants and media representatives, who give advice on the publication of sensitive stories.

The MoD declined to say why the future of the committee was being considered, but minutes of its latest meeting say: "The events of the last few months had undoubtedly raised questions in some minds about the system's future usefulness."

In his latest report, its secretary, Air Vice-Marshal Andrew Vallance, raised concerns about the parallel publication of Snowden's revelations by newspapers around the world, noting that at the outset the Guardian had "avoided engaging with the DA-notice system before publishing the first tranche of information".

However, giving evidence to MPs in December, Alan Rusbridger, the editor of the Guardian, said the D-notice committee had found nothing published by the paper that put British lives at risk. He said the Guardian had consulted government officials and intelligence agencies – including the FBI, GCHQ, the White House and the Cabinet Office – on more than 100 occasions before the publication of stories. On only one occasion was there no consultation with the UK government before publication, when the editor feared an injunction could be sought, he said.

Compliance with D-notices is not compulsory, but there are fears the system could become more draconian after a review.

Simon Bucks, associate editor at Sky News and the D-notice committee's media vice-chairman, told the Sunday Times: "Any suggestion that the current system be abolished would potentially be a precursor of a coercive system, which I believe the entire British media would oppose."

A spokesman for the MoD said the department was "considering a review of the system", but no decisions had been made. There are currently five standing D-notices relating to military operations, nuclear weapons, ciphers and secure communications, sensitive installations and the security services.