A mysterious “unidentified” golden dome has bewildered Australian police, prompting the federal and state authorities to investigate the item.

The giant metal object, which looked like some kind of disjointed piece, was found by locals at the West Australian beach, about 250km north of Perth, BBC reported.

According to initial information, the object was not part of any commercial aircraft. The authorities have treated it as “hazardous” and police have urged people to keep a safe distance.

“We want to reassure the community that we are actively engaged in a collaborative effort with various State and Federal agencies to determine the object’s origin and nature,” police said in a statement.

Military and Australia’s space agency are part of the team investigating the object.

It was about 2.5m wide and between 2.5m and 3m long, Australia’s public broadcaster reported while quoting Green Head beach residents. They got to know about the object on July 15 night.

It was a “great social evening”, as per the description of one local. “It was a lovely, still night, the kids were digging sand castles around it,” he told the ABC.

But aviation expert Geoffrey Thomas was of the view that it was apparently a fuel tank from a rocket. He added that it might have fallen into the Indian Ocean at some stage in the past 12 months.

It was possible the giant cylinder could have fallen from a “foreign space launch vehicle”, the Australian Space Agency said.

Some experts believed that the cylinder might be from an Indian rocket. But the veracity of such claims would be confirmed after seeing the serial or catalogue number.

There were rumours that the object was part of MH370 – a plane that went missing off the west Australian coast in 2014 – but Thomas thinks otherwise.

“It’s not any part of a Boeing 777 and the fact is MH370 was lost nine-and-a-half years ago so it would show a great deal more wear and tear on the debris,” he said.