AFP commissioner Reece Kershaw told a Senate hearing on Thursday he had received the referral from Treasury.

Treasury says PwC’s former head of international tax Peter Collins improperly used confidential commonwealth information, prompting the AFP referral to consider if criminal charges should be brought.

“The emails that the Tax Practitioners Board tabled in Parliament on May 2, 2023 highlighted 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,” a Treasury statement said.

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

Treasury said Collins shared Treasury information on measures to bolster tax laws, including rules stopping multinationals from lowering their tax bill by shifting profits from Australia to other jurisdictions.

AFP deputy commissioner Ian McCartney told the Senate committee on Thursday morning that the investigation could be broadened beyond the one identified PwC employee.

“We will seek to identify other persons who allegedly committed an offence,” he said.

McCartney said the investigation would be thorough, but it was at an early stage.

“We’ve designated this matter as a sensitive investigation … for us, it’s a priority investigation,” he said

PwC’s CEO has also stepped down and the firm has announced an investigation into its governance, culture and accountability led by former Telstra boss Ziggy Switkowski.

Home Affairs Minister Clare O’Neil said PwC’s actions were “a grotesque betrayal of trust”.

“I can just absolutely tell you the Australian government takes this incredibly seriously,” she said.

“We are looking at a whole of government response to this, which the minister for finance in particular is involved in.

“We will not stop until we get to the bottom of exactly what has happened here. It is a disgraceful incident and it must be properly investigated and the people responsible held to account.”

Finance Minister Katy Gallagher, who will appear at a Senate estimates hearing alongside officials in Canberra on Thursday, called PwC’s behaviour “outrageous”.

Gallagher said it seriously challenged the trust between government and such private sector firms, and the government would look to reduce its reliance on consultants.

Senators were told yesterday that the attorney-general’s department was “having another look” at a contract with PwC for managing workflow.

Centre for Public Integrity research shows the volume of contracts with the “big four” consultancies – PwC, KPMG, EY and Deloitte – has surged 400 per cent in the past decade.

In 2021/22, the public service contracted $1.4 billion with the four firms.

-with AAP