Embattled consultancy firm PwC has stood down nine partners as its head issued a public apology over the widening tax advice scandal.

In an open letter, acting chief executive Kristin Stubbins said members of the company sharing confidential tax policy from the Treasury department were “betraying the trust placed in us”.

The letter said nine partners had been sent on leave effective immediately. They include members of PwC’s executive board and governance board.

Ms Stubbins said the company had failed in multiple ways, due to a lack of confidentiality and poor governance,

“No amount of words can make it right. But I am fully committed to taking all necessary actions to re-earn the trust of our stakeholders,” she said.

“We understand that we betrayed the trust of our stakeholders and we apologise unreservedly. We know that action is critical to restore confidence in our firm and rebuild trust with our stakeholders and I am committed to taking all necessary steps to make this happen.”

Two independent non-executive directors have been appointed to PwC’s governance board following the emergence of the scandal.

Ms Stubbins said PwC had started work to “ring fence” services it was already providing to the federal government.

An independent report into the scandal, headed up by former Telstra boss Ziggy Switkowski will be released, but not until September.

“We recognise that enhanced governance, structures and controls are necessary and the decision to ring fence our federal government business is a critical next step,” Ms Stubbins said.

Monday’s development came as Prime Minister Anthony Albanese said the list of employees allegedly involved in the tax advice scandal should be made public.

Mr Albanese described the scandal as a terrible indictment and said transparency was needed on what took place.

“All of this should become public at the appropriate time. Of course, there are investigations under way and I don’t want to say anything to interfere with those processes,” he told Sydney radio station 2SM on Monday.

“Quite clearly, what went on there is completely unacceptable.”

During Senate estimates hearings last week, the Greens sought to release the list of names of employees who had leaked confidential Treasury information.

But finance department officials said naming the partners involved in the tax advice scandal could disrupt the criminal investigation.

Mr Albanese said it was crucial the scandal was investigated.

“In the fullness of time, of course, there needs to be proper transparency about all of this,” he said.

“This is the fault of PwC, as soon as it has come to light, there are now appropriate investigations taking place.”

Federal police are investigating, following a referral by the Treasury Department.

Mr Albanese said the leak reinforced the need to bolster the federal public service.

“Any government department undertaking work needs to bear in mind the ethical considerations that come from this PwC behaviour,” he said.

“There’s also been over a period of time a loss in the capacity of the federal public service to provide that internal advice and avoid all of these risks, all of these for-profit motives.”

PwC had agreed to stand down staff who knew about the Treasury leaks from working on government contracts.

-with AAP