Detectives from NSW Police are seeking information from NAB about if and when Mr Thorburn reimbursed the company behind the gifts, the Human Group, and about the circumstances of the company's decision to pay for the holiday and kitchen appliance and whether there was any discount to the market value of the gifts.

Sources said it is possible Mr Thorburn was not aware of the Human Group’s involvement because he may have been misled by someone involved in the transactions.

NAB confirmed to Fairfax Media on Thursday that Mr Thorburn had made unintentional breaches of group policy in relation to the Fiji trip and the Thermomix.

Explaining the reasons for the pay cut, NAB also noted in its annual report both the reputational impact of the royal commission and Mr Thorburn's breaches of company policy relating to declaration of gifts.

"The group CEO has accepted accountability for NAB’s failure to fix mistakes quickly, remediate customers promptly and set things right. These failures have impacted NAB's reputation," the annual report said.

"In addition, certain matters emerged in the course of an investigation into an alleged fraud on NAB by a former employee and supplier to NAB. These included certain control failings and breaches of policy in the office of the CEO, and a small number of unintended breaches of policy by the group CEO."

"These matters have been resolved and closed to the board's satisfaction. The board and group CEO take all of these matters seriously."

The board also considered positive elements of Mr Thorburn's performance in determining his pay for 2018. This included leading the transformation of the bank and pursuing growth opportunities as well as developing a customer centred culture.

On balance, the board decided to award Mr Thorburn just 45 per cent of his bonuses and $3 million less than the total remuneration he could have earned if the bank and Mr Thorburn had a perfect performance during the year.

Other executives also took hefty pay cuts.

Former senior executive Andrew Hagger, who according to the annual report left the bank two days ago, received only 17.5 per cent of his variable remuneration during 2018. Mr Hagger stepped down from his role as chief customer officer in the bank's wealth division after his appearance at the royal commission.

His total remuneration for 2018 was slightly higher at $3.7 million due to a $752,351 termination payment.

Former NSW Premier Mike Baird, who stepped up after Mr Hagger's departure to become chief customer officer of consumer banking at the bank, saw his total remuneration jump to $2.28 million. He joined the bank in February 2017. Mr Baird's total remuneration between February and September 2017 was $886,845.