KPMG's chairman-to-be has apologised to a federal senator for discrediting her account of whistleblower allegations against the consulting giant.
Michael Ebeid, who was appointed subject to partner approval in July, issued the mea culpa in an email to Labor senator Deborah O'Neill on Saturday.
The missive was published on Monday by a parliamentary committee, chaired by Senator O'Neill, probing alleged audit misconduct at the firm.
In it, Mr Ebeid apologises for an internal email he sent in March, in which he described whistleblower allegations against the firm, raised by Senator O'Neill, as false.
"What I wrote was wrong," he said in the email, under the subject line "Apology".
"I described statements about the whistleblower's allegations made by you to the Senate as false. I described the firm's process as thorough.
"Events since have shown that neither was true, and that the concerns you raised on the whistleblower's behalf have helped uncover serious wrongdoing and I can only thank you for that."
He admitted he did not have all the facts at the time and thought he was being helpful, including by wanting to meet with Senator O'Neill.
"However, with what I know now, my email was naive, embarrassing and wrong on every level," he said.
The apology to Senator O'Neill was overdue, he said, and made in addition to a separate apology for the email issued through the committee in July.
KPMG has been engulfed in scandal since March, when Senator O'Neill shared whistleblower allegations against the firm with parliament.
They included claims KPMG partners accessed confidential information from client Lendlease to pitch for and win lucrative audit contracts.
The allegations led the firm's chief executive to resign and its national chair and audit partners to leave the company, and sparked a sector-wide investigation by the corporate watchdog.
Mr Ebeid previously served as chief executive at broadcaster SBS Australia and as group executive for Telstra.
He was nominated to lead KPMG in July after former chair Martin Sheppard resigned.
The parliamentary joint committee on corporations and financial services, chaired by Senator O'Neill, will hold its next public hearing on Friday.
