Treasury secretary Steven Kennedy has declined to comment on action being taken against global consultant PwC for fear of prejudicing a police investigation.

Dr Kennedy made a brief statement to a Senate estimates hearing in Canberra on Tuesday, following Treasury’s referral of former PwC partner Peter Collins to the Australian Federal Police last week.

The referral came after the Tax Practitioners Board investigated Mr Collins and found he had failed to act with integrity – under his professional, ethical and legal obligations – and terminated his tax agent registration for two years.

The board also ordered PwC to take steps to ensure it managed conflicts of interest appropriately.

The findings were published in January.

In May, emails were tabled in parliament highlighting what Dr Kennedy described as “the significant extent of the unauthorised disclosure of confidential Commonwealth information and the wide range of individuals within PwC who were directly and indirectly privy to the confidential information”.

“In light of these recent revelations and the seriousness of this misconduct, Treasury referred the matter to the Australian Federal Police to consider commencement of a criminal investigation,” he told the hearing.

“Treasury is not able to comment further on the AFP referral or on the specifics of any other potential action so as to not prejudice those options.

“Evidence that we give today will be careful to avoid prejudicing any police investigation.”

On Monday, PwC announced it was standing down nine partners, including members of its executive and governance boards.

Acting chief executive Kristin Stubbins said members of the company who shared Treasury’s plans had betrayed “the trust placed in us”.

“We understand that we betrayed the trust of our stakeholders and we apologise unreservedly,” she said.

“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.”

The Greens are seeking to release the names of PwC employees via a Senate committee.

But the committee is seeking advice from the Senate clerk about whether revealing the list could disrupt criminal investigations.

Greens senator Barbara Pocock, who tried to table the list of names, said steps taken by PwC were “too little, too late”.

“We know this is a company with tentacles across business and certainly into government, so we need to know much more about the wider group of people who’ve been engaged in this terrible chapter,” she told the ABC.

“PwC continues to conceal and fail to really come clean.

“We need transparency and honesty and a proper clean-up.”

Prime Minister Anthony Albanese said the list of employees allegedly involved in the tax advice scandal should be made public.

“All of this should become public at the appropriate time, of course,” he said.

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

An independent report into the scandal, headed by former Telstra boss Ziggy Switkowski, will be released in September.

– AAP