Two Hamilton residents have discovered a human bone in a dirt bank under a suburban home.
Police say it was initially thought the bone may have belonged to an animal, but analysis by a pathologist has identified it as a human thigh bone.
Detective Senior Sergeant Karl Thornton says the bone was found in a very brittle and dry state.
"As yet we have been unable to determine its age other than an estimate of it being between 20 and 100 years old," he said.
Police will be consulting with forensic, iwi and history experts as they try to identify the bone, which was found earlier this week.
Det Sen Sgt Thornton says there are no reports of missing people or unaccounted for bodies that could be directly linked to the bone's discovery.
There are also no known historical burial sites in the area.
The site where the bone was found was blessed by local iwi on Thursday.
Hamilton City Council building inspectors will check the site to make sure it is safe for further excavation.
The bone is going to be further analysed by a forensic anthropologist.