A corporate travel scandal at NAB is reportedly looking at more than $110 million worth of trips

The former chief of staff to three NAB CEOs, including Andrew Thorburn, has had her bank accounts frozen as part of an ongoing investigation by the NSW Crime Commission over potential kickbacks from a corporate travel company, The Australian reports.

Your Money chief reporter Leo Shanahan says the investigation involves a decade of corporate travel supplied to the NAB by The Human Group while Rosemary Rogers was the the bank CEO chief of staff and involves up to $113 million worth of company trips.

The Melbourne-based former NAB executive had her bank accounts frozen by the crime commission on Tuesday.

The Australian says police are investigating whether kickbacks were paid to bank staff as part of inflated travel contracts. Human Group director and founder Helen Rosamond is also part of the investigation. No charges have been laid.

Rogers resigned from her role 12 months ago after 20 years at the bank. Thorburn told staff in a note at the time that she had made a “lapse in judgment” and when the allegations first emerged publicly in April, following raids in both Sydney and Melbourne, said he was personally hurt.

The NAB said in a statement that the alleged fraud was reported by a whistleblower.

"NAB responded and acted immediately on Andrew Thorburn’s direction, investigated matters and reported them to police,” the statement said.

“If the alleged fraud is proven, it represents a most serious breach of trust by a former employee."

The CEO is not part of the investigation.

There's more from The Australian here.