At the same time , Vice Admiral Shigeyoshi Inoue , commander of the IJN 's 4th Fleet ( also called the South Seas Force ) which consisted of most of the naval units in the South Pacific area , advocated the occupation of Tulagi in the southeastern Solomon Islands and Port Moresby in New Guinea , which would put northern Australia within range of Japanese land-based aircraft .
Vice Admiral Shigeyoshi Inoue , commander of the IJN 's 4th Fleet ( also called the South Seas Force ) had the idea of capturing Tulagi in the southeastern Solomon Islands and Port Moresby in New Guinea . This would put northern Australia within range of Japanese land-based aircraft .