Former NAB chief executive Andrew Thorburn didn't believe an anonymous whistleblower letter accusing his trusted chief of staff of illegal financial activity, a jury has been told.
But he said Rosemary Rogers then admitted that $1.5 million in her account came from businesswoman Helen Rosamond, who is now on trial in the NSW District Court.
The 47-year-old former chief executive of events and human resources company Human Group has pleaded not guilty to dozens of fraud and bribery charges related to allegedly defrauding the bank of millions of dollars between 2013 and 2017.
The Crown alleges Rosamond sent falsified and inflated invoices from Human Group to NAB and paid millions of dollars in kickbacks to Rogers to ensure they were paid.
Giving evidence on Thursday, Mr Thorburn said he was NAB chief executive from 2014 to 2019 and retained Rogers as chief of staff from his predecessor.
"From everything I saw, she was competent, professional and got things done and had a real knowledge of the bank," he said.
Rogers, authorised to approve payments of up to $20 million, had responsibilities including organising meetings in the bank buildings, off-site conferences and shorter events.
He did not know how much the events cost NAB.
"I had no reason to doubt Rose's competence and trustworthiness," he said, noting she had done the job for years.
He did not discuss with her the contracting out of work to another company, leaving it to her to organise how it happened and who she used.
Rogers and his executive assistant organised his business travel and sometimes his personal travel, the latter invoices being paid by him personally.
He first met Rosamond at a bank event in around 2005 and understood that her company Human Resources organised events, including for NAB.
He had very little interaction with her, noting it was primarily Rogers' role to organise the events which were successful and very well conducted.
The prosecutor has alleged that among the largest of the allegedly fraudulent invoices issued was one for $2.2 million, purportedly for "Project Eagle".
Mr Thorburn said he did not know this was the confidential codename given for the project recruiting former NSW premier Mike Baird as an NAB executive in 2017.
Rogers made the arrangements for him to meet Mr Baird at the Langham hotel in Sydney, but she did not attend the meeting.
He said Rosamond greeted him at the hotel, but other than that she was not involved in Mr Baird's recruitment.
In December 2017, he heard from the bank's internal auditor who wanted to see him urgently and came to his house.
An anonymous whistleblower letter said Rogers had received around $1.5 million, also claiming "a number of other things that had been illegally gained".
"I didn't believe it," he said.
She had worked for him for years, had always been very helpful, was a good competent worker, worked hard and he trusted her.
"I just didn't believe she would do anything like that."
But after an investigation, he was told it was true and the money was in her account.
"Rose accepted that the money was from Helen as part settlement for a house.
"She admitted it, said it was a single mistake and nothing else like that had happened."
The trial continues.
