One of Australia's top journalists has revealed that a whistleblower source for a groundbreaking scoop "absolutely freaked out" and almost pulled out of the story after seeing federal police raid the national broadcaster and a journalist's home in June.

Adele Ferguson is an investigative journalist with The Age newspaper who has won Australia's top journalism prize, the Gold Walkley. Her work sparked the explosive royal commission into misconduct in the banking industry, established in December 2017.

After the royal commission wrapped in February 2019, the whistleblower leaked a trove of confidential documents to Ferguson, raising questions about National Australia Bank's (NAB) risk management and conflicts of interest with its auditor, EY.



Ferguson would eventually write about the documents in a chapter of her new book, Banking Bad, and in stories published in Australian and New Zealand national newspapers.

The revelations — among them NAB chairman Ken Henry privately admitting his bank was still selling products that ripped off consumers even as the royal commission was underway — caused shockwaves.