The Law Council of Australia has defended the integrity of the Victorian legal profession in the wake of the Lawyer X scandal, following “troubling” revelations that as many as six lawyers had acted as informants to Victoria police.

The information was disclosed to the royal commission on police informants last week, along with information that Lawyer X, known as Informer 3838, was first registered as a police informant in 1995, 10 years earlier than previously thought.

The wider date range prompted former South Australian police commissioner Malcolm Hyde to resign as commissioner over concerns of a perceived conflict of interest, because he held a senior position in Victoria Police until 1997.

Attorney general Jill Hennessy told reporters that “a number of other informants have been identified and willingly disclosed” to the royal commission.

Hennessy would not say if any of those lawyers were current informants but said she was “confident in the royal commission’s power to be able to advise anybody if there is any inappropriate current practice”.

It’s understood that up to six lawyers have been implicated.

Law Council of Australia president Arthur Moses SC told Radio National that the revelations were “very troubling” and criticised Victoria Police for allowing the practice to occur.

He said that lawyers were only allowed to breach client privilege in “exceptional circumstances” when the safety of a member of the public was at stake.

“For instance if a client tells you that they are going to murder somebody or assault somebody there are exceptions in the ethical obligations of lawyers in those circumstances,” he said.

Asked if he was aware of similar arrangements between lawyers and police in New South Wales, Moses said he was “not at liberty to disclose matters” that were not in the public realm.

In a statement, NSW Bar Association president Tim Game SC said the association had met with the director of public prosecutions, the NSW Crime Commission, the Law Enforcement Commission and NSW police to discuss the issue of lawyers acting as informants, and he expected “to be in a position to make further comment in the near future”.

NSW Police said it had audited its informant register dating back to 2003.

“No evidence of alleged breaches of legal professional privilege have been identified nor has any conduct similar to that alleged in the Victorian ‘Lawyer X’ matter become apparent,” it said in a statement.

Law Institute of Victoria president Stuart Webb said in a memorandum to members on Wednesday that the organisation was “unaware of any other legal professionals who have breached any obligations of confidentiality”.

“We support the royal commission and its work, and support remedies to ensure the integrity of the justice system is upheld,” Webb said.

Victoria Police said that it was unaware until recently that Lawyer X had been registered as an informer in 1995, two years after a good behaviour bond was given for a drug charge that saw two co-accused convicted of drug trafficking.

“This information had not previously been identified due to shortcomings in our record keeping practices related to informers in the mid-1990s,” police said in a statement. “These practices have since been comprehensively improved.”

Hennessy said the royal commission was still expected to hand down its preliminary findings on 1 July and that Hyde would not be replaced as a commissioner.

Instead chief commissioner Margaret McMurdo will conduct the commission alone and call on outside experts “in the event that she requires the advice and the assistance of those that understand operational intelligence [and] informant management practices.”

The royal commission will hold its first directions hearing on 15 February.