Stuart Webb, president of the Law Institute of Victoria, told The Age that despite the risks, the integrity of the criminal justice system was more important than the anonymity of lawyers who snitched on their clients to police.

"We want to know who the people are," he said.

"The reputation of many of our lawyers – hard-earned reputations – is being damaged by discussions, gossip [and] inuendo."

"We are having reports of clients speaking to their lawyers and saying, 'How can I trust you?' And that's obviously, for us, a very significant concern."

The legal profession fears public confidence in the legal profession has been smashed by the deepening scandal, sparked by revelations about the woman known variously as Informer 3838, Lawyer X and EF in court judgments.

Informer 3838 was a Victorian defence barrister who acted as a registered police source for nearly 15 years while representing members of Melbourne’s underworld, including drug traffickers, murderers and Mafia figures.

In a clear breach of her ethical duties, she gave up information about clients even while she represented them.

Police have long argued that the safety of Informer 3838 is the key consideration in keeping her identity a secret.

But a High Court decision last year, which followed Supreme Court and Court of Appeal decisions, found the interests of justice outweighed her right to anonymity.

"The public interest in preserving EF's anonymity must be subordinated to the integrity of the criminal justice system," the judgment read.

The identity of Informer 3838 has yet to be disclosed publicly, but after the High Court decision the DPP was able to notify underworld figures, including drug kingpin Tony Mokbel and his shipping industry inside man Rob Karam, that their lawyer had become a police informer and given up information that put their convictions at risk.

The woman's identity is an open secret in legal and criminal circles.

But Mr Webb said if a police informer was in danger, it was the duty of police to protect them.

"That's [12] judges who've all said that the absolute confidence the public has to have in the institution of the court in the criminal justice system supercedes that interest of the individual," he said.

"Now the police can take steps to protect [the informer] as much as that person wishes to take advantage of it, but ... the most eminent legal minds in our community have said that."

Also on Thursday, Police Commissioner Graham Ashton confirmed for the first time the commission would explore whether five other secret police informers may have breached their professional obligations to maintaining their clients' privacy.

He denied the six informers – including Informer 3838 – were all lawyers, but refused to confirm their professions. The Age has previously reported the six could be lawyers, doctors or other legal and medical professionals.

Mr Webb said it was possible some, or even most, were lawyers.

"Any person could be a human source, [but] we would say that it's unethical for a lawyer to be one, because you don't know when your obligations on behalf of your client crosses that line. So we would not encourage any lawyer or law student to become a human source.

"So if people are acting in this way and they are breaching their obligations of privilege, you know, I don't think that they can remain as lawyers in our profession and I would seek to have them removed."

The only exception, he said, was a public-interest test when lawyers believed their client posed an immediate risk of harm to others.