A Japanese World War II submarine wreck was found partially buried in the seabed of a Papua New Guinea harbor during a search for unexploded munitions, Australia's military said Friday.
Australian and New Zealand warships found it 180 feet (55 meters) underwater while working in the area to clear WWII-era explosives Thursday, a Defense Department statement said.
Simpson Harbor is in the town of Rabaul, which was a major Japanese military base on the northeast coast of the South Pacific nation.
The wreck is partially buried in sand but upright. Australian navy historians had concluded from underwater images that the wreck is Japanese, the statement said.
"The Royal Australian Navy will now work with Japanese authorities to assist in determining the wreck's identity," it said.
Gary Oakley, an Australian War Memorial curator and a former submariner, said it appeared to be a midget submarine crewed by one or two men.
"My best guess would be it's a Japanese midget submarine. It doesn't look big enough to be an ocean-going ... submarine," Oakley said after examining indistinct images of the wreck released by the Defense Department.
Japanese midget submarines were transported by ship or larger submarines and used covertly to infiltrate enemy targets including Pearl Harbor in Hawaii and Sydney Harbor.
Such a submarine could have been destroyed by an American air raid or naval bombardment or even scuttled by the Japanese toward the end of the war, Oakley said.