BREAKING | Human bones found at Rottnest Island church, police investigating

Multiple bones were discovered on Wednesday morning during building works on church grounds on the island, sparking an immediate police investigation.

A WA Police spokeswoman confirmed officers were called to the scene following the find.

"Police will arrange forensic assessment of the bones to determine their age," she said.

"Inquiries are continuing."

Authorities have not revealed whether the bones were uncovered on the grounds of the island's Catholic or Anglican church. Both churches are within close proximity on the popular holiday destination located 18 kilometres off the coast of Fremantle.

Rottnest Island served as an Aboriginal prison from 1838 to 1931, during which time more than 3,700 First Nations men and boys were incarcerated.

Many died in custody and are believed to be buried on the island. There is ongoing search by families and researchers to locate and properly honour the remains of those who perished there.

It is not yet known whether the discovery is connected to that history, and police have given no indication of the likely age or origin of the bones pending formal forensic analysis.

Forensic examination will be required to establish whether the bones are of historical or more recent origin — a process that could take some time.

Police said inquiries were continuing.