World War IThe German protectorate covered Bismarck Archipelago and North-east New Guinea 1884-1914.
In one of the first actions of the First World War, Australian troops relieved the Germans of their territory in the Battle of Bita Paka. In 1921 the League of Nations gave German New Guinea to Australia.
World War II
Jan - Feb 1942. Bismarck Archipelago falls to Japan in the Battle of Rabaul.
The Japanese began preparing to invade Australia, which led to the Kokoda Track campaign beginning in July 1942, and the Battle of Milne Bay in August 1942.
Battle of Milne Bay
The Japanese were trying to knock out an airfield near Alotau, which risked their sealane south towards Australia. The Australians successfully defended against their attack.
The battle is considered to be the first in the Pacific campaign in which Allied troops decisively defeated Japanese land forces. Although Japanese land forces had experienced local setbacks elsewhere in the Pacific earlier in the war, unlike at Milne Bay, these actions had not forced them to withdraw completely and abandon their strategic objective. As a result of the battle, Allied morale was boosted and Milne Bay was developed into a major Allied base, which was used to mount subsequent operations in the region.
Siege of Rabaul (1943)
Allied forces attacked the Japanese base at Rabaul.
Allied advances 1942-44
Deboyne Island was a Japanese seaplane base during World War II.The Japanese found that their new base was just a little too close to the allied planes based at Port Moresby and the base was quickly abandoned. The Japanese never returned to the island however several ‘Zero’ fighter planes were ditched in the area during the Battle of the Coral Sea. One remains virtually intact in the shallow waters of Deboyne Lagoon.