Nobody was even looking for it... 

Visualisation of the shipwreck (Australian Institute of Marine Science/Business Insider)

A mystery shipwreck has been found by accident during a mapping survey off Australia's north-west coast.

The wreck was discovered in 60 metres of water by the Australian Institute of Marine Science (AIMS) off Broome in Western Australia.

The wreck suddenly appeared on the sonar of the RV (research vessel) Solande as it was scanning the seafloor.

"The ship's captain noticed the unusual formation on the echosounder while we were travelling between sites," says AIMS Marine Acoustics researcher Miles Parsons.

"We came back to take a closer look and were able to map it in incredible detail using enhanced multibeam survey technology onboard.

"It was pretty clear this was not a natural formation."

The wreck is made of metal, believed to be post 1900s, and is about 37 metres long.

Multibeam survey map and video footage has been given to the WA museum to help try to identify the ship.

The video footage shows an abundance of fish life:

"It's certainly not something you find everyday," says Parsons. "We will stay in touch with the WA Museum to see what they find."

He had watched in surprise as a large structure appeared on the sonar screen.

"There was a lot of excitement going on as the object popped up on our screen, and then there were a lot of phone calls going back and forth trying to work out what it was," he says.

"So we decided we had to go back and have another look and send a towed camera down, and there it was.

"It is exciting to find a shipwreck using our multibeam technology."

Here's a visualisation of the wreck: