One of the chief bodies investigating the PwC tax advice scandal says reams of documents relating to the matter are yet to be released as it works to determine which staff were involved in the breach.
Tax Practitioners Board chief executive Michael O'Neill told a Senate estimates hearing there might be thousands of documents relating to the confidentiality breach case that went beyond publicly released emails.
The documents spanned communications from the tax board, Australian Taxation Office and PwC, he said.
The consultancy firm has been under fire following revelations a former partner shared confidential tax information from Treasury in order to help clients sidestep a crackdown on multinationals' tax avoidance.
Mr O'Neill said the Tax Practitioners Board was working on a detailed list of names involved in the scandal based on the documents.
But he said the task was complicated by the fact that not all the people whose names appeared in the documents knew anything about the leaked government information.
The board confirmed it had no plan to suspend PwC, despite the revelations.
Reserve Bank governor Philip Lowe earlier confirmed the central bank had recruited the troubled consulting giant to assist it in correcting staff underpayments.
He told a parliamentary committee the central bank had discovered it was incorrectly paying entitlements when employees left the institution.
Dr Lowe said the bank was in the process of fixing the underpayments with the help of PwC, which it contracted late last year.
The appointment predated when the confidentiality breach scandal involving PwC first came to light, in January 2023.
The consultancy firm has been under fire following revelations staff shared confidential tax information from Treasury in order to help clients circumvent a crackdown on multinationals' tax avoidance.
The Australian Federal Police is investigating the leak.
Dr Lowe said he was appalled by the revelations.
"The use of private information of this sort for commercial gains is wrong," he said.
"It destroys trust ... it's unacceptable.
"It should come with very serious consequences for those who did the wrong thing."
The governor said the bank had one ongoing agreement with PwC for audit and risk management services.
"We're continuing to use them for that purpose and because the cost of having to change isn't worth the benefit we would get from that," he said.
Dr Lowe confirmed the bank would not take out new contracts with the firm until it produced a satisfactory response to the revelations.
Greens leader Adam Bandt challenged Prime Minister Anthony Albanese to refer the matter to the new National Anti-Corruption Commission, which is due to start work in July.
Mr Albanese said the confidentiality breach was an absolute scandal, which is why the matter had been referred to the AFP.
He said steps were being taken to strengthen government systems in light of the scandal.
"Secretaries have been reminded that ethical behaviour must be taken into account as part of the value-for-money assessments which underpin decisions under the procurement framework.
"These revelations are indeed shocking but they do point towards a policy failure as well, and that is what the government is addressing."
