A mysterious object that washed up on a remote beach in Western Australia is being treated as hazardous while authorities try to identify what it is.

Western Australia Police said an unidentified object washed up on a beach near Green Head, north of Perth, on Saturday afternoon.

Officers are working with state and federal agencies to figure out what the object is and where it came from.

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"In order to maintain the integrity of the investigation, officers from the Western Australia Police Force are currently guarding the object," police said.

"This measure has been taken to ensure the preservation of potential evidence and facilitate further expert examination.

"The object is being treated as hazardous, until the origin of it can be established.

"People in the area should keep a safe distance."

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Police said the object didn't originate from a commercial aircraft – including MH370, which vanished in March 2014.

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