A potential unexploded weapon from World War II has been discovered by divers conducting an underwater survey in Darwin Harbour.
The object, believed to be a possible live mortar, was found about 330 metres south of Darwin's East Arm barge ramp, according to the Northern Territory's Department of Infrastructure, Planning and Logistics.
The divers, conducting a survey on behalf of the department, were searching for potential weapons and heritage items left from WWII when they made the discovery on Monday.
Mariners are currently banned from entering an exclusion zone around the object of about 250 metres, which is marked by yellow floating buoys that will flash at night time.
Dive works have been suspended and the item has been reported to the Australian Defence Force, NT Police and the Acting Regional Harbour Master.
Defence is now working on a plan to safely extract the object, a spokesperson for the planning and logistics department said in a statement.
Any vessel or person located within the exclusion zone faces a fine from Northern Territory water police officers.
The bombing of Darwin during World War II remains the deadliest and largest single attack by a foreign power on Australian soil in modern history.
It's not the first time a remnant from the war has been unearthed in the city, which was the target of devastating Japanese air raids on February 19, 1942.
In 2015, a road crew working near the city centre unearthed an unexploded Japanese bomb on the main arterial road, Tiger Brennan Drive.
In 2010, a motorist driving along the same road spotted a bomb crater in an embankment, later reporting the sighting to heritage experts who confirmed the find.
The bombings remains the largest single attack ever mounted by a foreign power on Australian soil.
