Climate change could be affecting sacred Māori burial sites, iwi and a Department of Conservation historic adviser fear.
Erosion within the Waimea Inlet in Nelson has recently revealed human bones.
Local iwi said a human jawbone found recently in the Nelson inlet, followed soon after by the discovery of a legbone in the tidal zone below a sandbank, most likely belonged to a member of one of the many tribes who once inhabited the area.
Police were confident the bones were not linked to any open investigation or missing person case.
Department of Conservation historic adviser Steve Bagley said such discoveries could have a major impact on historic records, and they were likely to increase with the effects of climate change on sea level rise and erosion.
"Coastal erosion over the years has frequently turned up kōiwi and bones in sites like this. A lot of human occupation was coastal sites, and as sea levels rise coastal erosion will increase - and archaeologists are very concerned about the impact on the archaelogical record," Mr Bagley said.
There were protocols that must be followed with the discovery of human bones, including notifying police, he said.
"There's a legal requirement to report it to the police, so it can be followed up. It's also important we know exactly where it is."
The jawbone found in the inlet on New Year's Day was fully exposed in the sand. The person who found it phoned the police non-emergency number, who asked her to bring it into the Nelson station.
A police spokesperson told RNZ they would generally advise people who found an object or remnant like this to leave it where it was and report it to them.
It was not the first human bone to be found in the area, police said. A similar remnant was found about two years ago in the same area, identified as Māori and reburied by DOC and local iwi.
DOC pou tairangahau (cultural adviser) Barney Thomas said if a discovery was not at risk of being washed away by the tide, the first thing to do was mark the spot, inform the police, DOC or the landowner.
"The process is we need to inform the police and the historic places trust. Iwi become involved as well so it's about making sure the kōiwi are safe," Mr Thomas said.
The bones found recently have now been re-interred in a location near where they were found.