The Surveyor-General is giving evidence in a High Court case in a boundary dispute involving beachfront land at Matapouri Bay, near Whangarei.
The Whanau o Rangiwhakaahu hapu is suing the Crown for damages, alleging it failed to protect just over 1 hectare of land the hapu sold to the Crown in 1970 as part of a reserve.
The land involved is just over a hectare of prime beachfront at popular Matapouri Bay.
After mounting community pressure, the Crown bought the land in January from the Ringer family.
The family had commissioned several surveys over the years to try to determine their boundary with the Otito reserve.
Surveys dating back to the1860s give conflicting information, but a 1991 survey confirmed the Ringers' belief that the boundary was a stream.
Maori say that would put important wahi tapu inside the Ringers' property, and the real boundary was further south.
Although the land is now reserve, as the plaintiffs wanted, they are seeking costs and damages, and want the High Court to rule on the boundary issue.
Surveyor-General Donald Grant has backed the 1991 survey but says the case may have implications for other landowners and he welcomes the court's inquiry. Mr Grant was to give evidence to the court on Wednesday.