The Serious Fraud Office is investigating the Waitangi National Trust, which manages the Waitangi Treaty Grounds.
Waitangi National Trust Board acting chairman Dennis McBrearty said the board had discovered "financial irregularities".
"An investigation was conducted as soon as the irregularity was discovered by the organisation, but this had now been passed to the Serious Fraud Office (SFO)," he said in a statement.
"The matter is now with the SFO and we will await the findings of their official enquiry. We are unable to comment any further pending the outcome of the SFO enquiry."