By Andrew Brown, Tess Ikonomou and Poppy Johnston in Canberra

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”.

Dr Kennedy said the emails were “pretty disturbing” by any community standards and prompted Treasury to refer the matter to police.

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

Labor senator Deborah O’Neill took the opportunity to read aloud some snippets from the email exchange, including a reference to the Australian Taxation Office “figuring out the joke” and “getting grumpy” in relation to the sharing of the confidential information.

Treasury Deputy Secretary Diane Brown, who is in charge of the revenue group, said the agency first became aware of a “possible breach of confidentiality” when contacted by the ATO in 2018.

She said the tax office was subject to “strict secrecy provisions” so it was unclear why the regulator needed information from Treasury about the incident.

In late 2020, the Tax Practitioners Board also asked for information from Treasury about PwC and its involvement in multinational tax consultations.

Ms Brown told the hearing it was not unusual for regulators to seek this kind of information and it was her understanding that the treasurer at the time was not advised about the investigation.

The consultancy giant has already kicked off an internal investigation into the incident and the broader culture at the firm, and on Monday, announced it was standing down nine partners.

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 involved via a Senate committee.

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