Treasury officials have been accused of being asleep at the wheel in dealing with breaches of confidential government information.
Officials were grilled on their knowledge of potential breaches of Treasury tax information by former PwC partner Peter Collins, who has been referred to federal police to investigate the allegations.
Treasury officials said they became aware of a possible breach in September 2018, several months after Mr Collins signed a new confidentiality agreement
A Senate committee was told Treasury had very little information on the possible breach at the time and they passed that on to the Australian Tax Office for its investigation.
But Greens senator Barbara Pocock said further precautions should have been taken.
"A possible breach of something with a criminal consequence comes to you and you don't have alarm bells go off? I am shocked," she said.
"That is inappropriate. That is sleeping at the wheel in my view, this is a very important matter with millions and millions of dollars."
Treasury deputy secretary Roxanne Kelley told the inquiry a review of secrecy provisions would prevent there being a repeat of information not being able to be shared between the department and the ATO.
"We understand the public consultation on that review has finished and (the attorney-general's department) is in the throes of finalising the report," she said.
KPMG chief executive Andrew Yates told the inquiry the conduct of rival consultancy firm PwC was "unethical and unacceptable".
Mr Yates said his firm supported a review by the government into whether the Australian Securities and Investments Commission should have more of a regulatory role for the profession.
"We recommend the introduction of an integrity charter for working with the Australian public service," he said.
"At the end of every piece of work, the government could assess compliance with the charter.
"While we are committed to exhibiting the highest standards of personal and professional integrity, we're not claiming to be perfect - there have been cases in the past where we've made mistakes in regard to the high-profile cases over recent years."
Finance department officials told the committee all Commonwealth contracts had conflict-of-interest clauses and required people who accessed sensitive data to sign confidentiality arrangements.
Deputy secretary Andrew Danks said unauthorised information-sharing would trigger a breach but departments needed to take a "contract management approach" to find out if this had occurred.
"We can't go into every consultancy to see who has got our information," he said.
"But if we do find out that things have been released or confidential information has been breached, that's where we have the termination clauses in contracts to consider."
The committee considered publishing the names of the 72 PwC staff involved in the recent scandal but ultimately decided against it.
Senator Pocock told reporters she hoped the names would eventually be released.
"Some names on this list may well be innocent people who received an email - we know many others are not," she said.
"PwC knows who has done what and when, and they should be taking responsibility, rather than leaning on the Senate."
