The man, who didn’t want to be named, came forward after visiting Katherine recently, where he heard about a spate of sightings of unexplained lights and objects in the sky.

The 39-year-old man said he was working on the guided missile destroyer HMAS Brisbane in 1992 as quartermaster gunner when an “illuminating, bright light” appeared in front of the boat.

“We were sailing in the Great Australia Bight when the light was suddenly in front of us, about 45 degrees, high in the sky.

“We watched it for about half an hour – but nothing was on the radar.”

The Navy Reservist said the light then “quickly moved to south east and then south west and gave a bit of a jiggle”, before it “shot up and disappeared”.

“All this took place almost 20 years ago, but it is something I’ve never forgotten and never will.

“I’ve never seen anything like it since.”

Watch video footage of the HMAS Brisbane from 1992 here

Th e guided missile destroyer was scuttled in July 2005 near Mudjimba Island on Queensland’s Sunshine Coast and a marine park has been proclaimed around the wreck.

Earlier this year an investigation into documented UFO sightings in Australia found that the country's X-files have gone missing.

The Defence Department spent two months searching its offices for files of a ''schedule of records … which relate to unidentified flying objects''.

But in late May, the department's FOI assistant director, Natalie Carpenter, wrote in a statement the only file Defence was able to locate was titled ''Report on UFOs/Strange Occurrences and Phenomena in Woomera''; the others had been destroyed.