PriceWaterHouse Coopers (PwC) insists it will comply with a request to hand over information to the Tax Practitioners Board (TPB) that is again looking into the leaking of confidential treasury documents.
On Monday, the accounting and consultancy firm directed nine of its partners to take leave pending the outcome of an internal investigation that is examining the unauthorised sharing of confidential Australian government tax information several years ago.
The TPB, which is responsible for the registration and regulation of tax practitioners, confirmed it had asked PwC for the names.
Appearing before Senate Estimates in Canberra, TPB CEO secretary Michael O'Neill said there had been no response from PwC.
"We have not had an answer as of yet," he said.
A spokesman for PwC said the company would reply in due course.
"We can confirm we received the request yesterday evening with a deadline of 20 June," the spokesman said in a statement.
"We will respond in accordance with the TPB's request."
Further investigations
In January this year, the TPB found that Peter-John Collins, a former tax partner at PwC, had "failed to act with integrity, as required under his professional, ethical, and legal obligations".
The TPB's investigation confirmed Mr Collins was involved in confidential consultations with Treasury about changing tax laws, which he then made unauthorised disclosures about.
The TPB also found PwC had failed to "properly manage conflicts of interest, when this confidential law reform information was shared with partners and staff in their tax practice" and that PwC "breached its obligations under the law and the Code of Professional Conduct".
Mr O'Neill said there were "ongoing inquiries" into who was aware of confidential information being shared to help PwC clients dodge new tax laws.
"We are now looking at further inquiries that have a broader base than the first investigations," he said.
The TPB has compiled a list of names to try and determine who received the confidential information leaked by Mr Collins and ascertain who knew they were in receipt of the confidential information.
Greens Senator Barbara Pocock pressed TPB Chair Peter de Cure and Mr O'Neill for further detail about the new investigation.
"From what you have said today it seems you accept that Mr Collins was not the only partner of PwC who knowingly received and used confidential information improperly, have I understood that properly?" she said.
Both answered: "Yes".
PwC has not responded directly to questions about the new investigation that the TPB is undertaking.
However, a spokesman pointed to previous comments published by PwC that include a promise to publish the report of the independent review into the incident and outline any recommendations made.
Federal police are also looking into PwC's use of confidential Treasury material, after it initially determined it didn't have enough information to proceed with an investigation.
Penalties questioned
Mr Collins was deregistered as a tax agent for integrity breaches by the TPB and was banned for two years from re-registering.
Senator Pocock questioned why Mr Collins wasn't given the maximum penalty of five years.
Peter de Cure said several factors were considered when the decision was made.
"He had on a range of matters admitted his conduct, he had demonstrated remorse for his conduct, and he had advised us that he would cease to practise as a tax agent," he said.
Two of the three referees Mr Collins used in his application were partners at PwC.
Mr De Cure said he did not expect Mr Collins to reapply to be a tax agent.
Calls for referal to National Anti-Corruption Commission
The prime minister has labelled revelations about the extent of consultancy firm PwC's confidentiality breaches "deeply troubling".
The Greens have called for the matter to be referred to the National Anti-Corruption Commission, but during Question Time, Anthony Albanese insisted a police investigation was more significant than a potential NACC inquiry.
"The breaches in confidentiality by PwC is an absolute scandal and is deeply troubling," he told parliament.
"I'm sure that anyone who has a look at the details finds these revelations shocking.
"Treasury has referred the matter already to the Australian Federal Police."
In recent weeks, most Commonwealth departments have outlined their reliance on PwC for external contracts.
While some have not committed to a ban on using the company in the future, the Reserve Bank of Australia (RBA) Governor Philip Lowe described the tax leaks as "appalling".
He said PwC would be banned from RBA work until it showed "complete transparency and accountability".
Assistant Treasurer Stephen Jones said it was an issue all departments, and the government should consider.
"The amount of money we're spending on contractors makes my eyes water and I think a lot of the work could be done better in-house," he said.
