Police are working to determine the origin of bones discovered in the sand dunes at Ninety Mile Beach.
The bones were found by a member of the public at the Far North beach on Monday night.
Police northern communications inspector Ben Offner said it's not yet known whether the bones are human.
"We will not know what their origins are until they have been examined by a forensic pathologist," he told NZ Newswire.
Insp Offner said sheep, beef and seal bones are regularly recovered in all sorts of places.
"The bones of a seal fin actually look remarkably like a human hand."
Insp Offner said sometimes historic human remains are found when Maori burial grounds are inadvertently uncovered.
"So there are totally innocent explanations as well."
He said the forensic examinations are likely to take a couple of days.
NZN