The Serious Fraud Office is investigating the Wellington Tenths Trust, which looks after Maori reserve land.
The SFO says the investigation is at an early stage, but it is classing it as a priority case.
It says it is inappropriate to jump to conclusions at this stage and will not comment further while the investigation takes place.
The Wellington Tenths Trust administers land in urban Wellington, as well as Kaitoke and Upper Hutt.
