KPMG chair Martin Sheppard and two audit partners are leaving the accounting and consulting giant in the wake of a scandal over misuse of confidential client information and the alleged mistreatment of a whistleblower.

The former executive whose concerns about the inappropriate use of confidential client documents sparked a crisis at the firm says he regrets coming forward.

The move comes after a difficult parliamentary hearing which grilled several people connected to a growing scandal over the misuse of confidential client files.