Detectives have charged a Sydney company director with more than 50 offences over an alleged fraud against NAB totalling $40 million over five years.
NSW Police on Friday arrested Human Group director Helen Rosamond, 43, at her Potts Point home and took her to Kings Cross police station where she was charged with 56 bribery charges and one count of obtaining benefit by deception and one count of attempting fraud.
She allegedly forked out more than $6.6 million to cover personal expenses for others to maintain a relationship with NAB.
The bribes were used to retain contracts and overpay legitimate invoices.
Acting Assistant Commissioner Stuart Smith alleges the "corporate corruption" committed by the financial training company involved "senior executives".
An NAB spokesperson on Friday said the alleged fraud against the bank was first reported by a whistleblower.
"NAB responded immediately, investigated and reported it to police," the spokesperson said in a statement.

The bank stressed that "NAB is the victim in this matter". Source: AAP
"If the alleged fraud is proven, it represents a most serious breach of trust by a former employee."
The bank stressed that "NAB is the victim in this matter".
"Police have confirmed that no one at NAB is under investigation, including former CEO Andrew Thorburn, and there is no suggestion of any wrongdoing by anyone at NAB."
Rosamond is the owner of the training company, Mr Smith said.
The acting assistant commissioner told reporters the total amount involved in the alleged fraud was some $40 million. The criminal behaviour occurred between 2013 and 2017, he added.
The relationship between Human Group and NAB dates back 12 years, with contracts worth $118 million.
"I won't rule out further charges or further arrests," Mr Smith said.
Asked about the scale of the alleged fraud he noted: "The involvement of CEOs and very senior executives is something that we haven't seen before."
He noted everyone "watched in horror" when the 2017 royal commission into the banking sector uncovered some "pretty poor behaviour".
Rosamond is expected to appear in Sydney's Central Local Court on Friday.