A parliamentary committee has described the actions of consulting firm PwC in monetising confidential federal government information as "a calculated breach of trust".

But it has stopped short of publicly releasing a list of dozens of people who sent or received emails containing confidential information within the firm.

PwC has been under fire for months after revelations a former partner at the firm shared information taken from confidential Treasury briefings.

The Treasury was seeking the firm's input as it shaped new laws targeting multinational tax avoidance — information that PwC later used to help its clients work around the laws.

A trove of emails was publicly released through a Senate committee last month, revealing at times open discussion of confidential Treasury information on the new tax policies.

The matter is now the subject of a police investigation, and the parliamentary inquiry has been running alongside it.

A new interim report lays out what is now publicly known about the tax leaks, and strongly recommends PwC publicly discloses more information about who was involved and in what capacity.

"This was a calculated breach of trust by PwC.

"There is no evidence that PwC colleagues or leaders called out this behaviour for years, up until it became publicly known in 2023."

It also finds the firm engaged in a long-running effort to hide its actions.

"PwC engaged in a deliberate strategy over many years to cover up the breach of confidentiality and the plan by PwC personnel to monetise it," it said.

List of names won't be released for now

The emails were produced by the Tax Practitioners Board (TPB), a somewhat-obscure agency that handed PwC and its former partner Peter-John Collins its first sanction over the tax leaks affair.

There has been a strong push from some within parliament to make public the names of dozens of people included on the emails released by the TPB.