World War II - South West Pacific 1943-45

Allied intentions for 1943 included plans to recapture the Solomons as far as southern Bougainville, the New Guinea coast as far as Madang and the west coast of New Britain. The establishment of airfields on Kiriwina and Woodlark Islands was also planned. A defensive posture was to be taken against any possible attack against northern Australia from the Merauke-Torres Strait area.¹¹⁵

By now, as in World War I, Australia was facing acute manpower problems from maintaining an Army of twelve divisions - a far larger number in proportion to population than Britain, America or Japan. Battle casualties and a high rate of tropical disease, particularly malaria and dysentry that had reduced the Army by the equivalent of a division.¹¹⁶The provisions of the Defence Act, preventing conscripts from serving outside Australian territory, compounded the manpower problem. Many militia units were already designated as AIF since three-quarters of their strengths were volunteers. In February 1943, an Act was passed allowing the militia to serve anywhere in the South West Pacific Area below the equator.¹¹⁷

By early 1943 the Japanese had heavily reinforced the Lae-Salamaua area and were exploiting to the south-east through Mubo to Wau, but were forced back to Mubo. In early March enemy attempts to reinforce Lae were defeated in the Battle of the Bismarck Sea.¹¹⁸ By 14 July, the 3^rd Division had cleared Mubo and then laid siege to Salamaua, held by the substantially reinforced Japanese 51^st Division. Salamaua fell on 11 September and Lae, following operations by the 7^th and 9^th Divisions to its west and east, fell on 16 September.¹¹⁹

The 7^th Division continued the offensive, moving up the Markham Valley and the Ramu River, to occupy Dumpu by 4 October. Although heavy fighting developed on Shaggy Ridge in the Finisterre Mountains to the north, Japanese resistance collapsed by the end of January 1944. Meanwhile, on 22 September, the 9^th Division had made a further landing north of Finschhafen. Bitter fighting followed, particularly for the possession of Sattelberg which did not fall until 24 November. By 8 December, the Japanese were in retreat, Sio falling on 15 January 1944.¹²⁰ The three AIF divisions were withdrawn for rest and retraining, being replaced by the 3^rd, 5^th and 11^th Militia Divisions.

Allied successes opened the way for a US invasion of the Phillipines. As Australia’s national strategy was focussed on clearing Japanese forces from New Guinea, Australian forces were used to relieve the US garrisons in these territories. Due to manpower problems, the relieving Australian forces were much smaller than the US garrisons.

The ensuing Australian campaigns have since been the subject of much debate. From October 1944 onwards the 3^rd Division and two independent brigades were moved to the Solomons, the 5^th Division was allotted to New Britain and the 6^thDivision to Aitape, while the 8^th Brigade continued its operations in the Madang-Sepik River area.¹²¹ Plans for 1945 committed I Corps (7^th and 9^th Divisions) to operations to the west of the American invasion of the Phillipines, to capture areas in Borneo suitable as naval and air bases for future operations, to capture and hold the Borneo oil installations and re-establish the Netherlands East Indies Government in Borneo.¹²²

On 29 November, the unofficial policy of live-and-let-live between the American and Japanese forces on Bougainville was broken by the 3^rd Division offensives to the north, across the centre and to the south of the Island. These continued, against periodic strong resistance and counter-attacks by the Japanese, through the first half of 1945.¹²³ On New Britain, operations against the main Japanese positions across the Gazelle Peninsula were launched by the 5^th Division, initially from Jacquinot Bay where it arrived in early November 1944. From mid-March the Division had reduced the Japanese garrison to such an extant that operational requirements were reduced to active patrolling forward of the secured areas.¹²⁴ Meanwhile in New Guinea, the 6^th Division developed its operations eastward along the coast from Aitape and through the Torricelli Ranges towards Wewak, which was secured by the end of May; operations continued against the Japanese forces which had withdrawn into the Prince Alexander Ranges until fighting ended in August 1945.¹²⁵

Operations on Borneo commenced eight days before the fighting in Europe ended. On 1 May 1945 the 9^th Division landed at Tarakan and against heavy opposition secured the airfield. However obstinate opposition by the Japanese continued around Tarakan until the enemy withdrew on 14 June, being pursued relentlessly until the ceasefire in August.¹²⁶ The 9^th Division, on 10 June, was committed to capturing Brunei following landings at Labuan, the Muara Islands and Brunei Bluff. On 1 July, on the other side of the island, the 7^th Division landed at Balikpapan in the largest amphibious assault undertaken by the Australians. After heavy fighting, the enemy withdrew on 21 July.¹²⁷

WORLD WAR II - SOUTH WEST PACIFIC 1943-45
WWII - South West Pacific 1941-42	WWII Army Casualties
Allied intentions for 1943 included plans to recapture the Solomons as far as southern Bougainville, the New Guinea coast as far as Madang and the west coast of New Britain. The establishment of airfields on Kiriwina and Woodlark Islands was also planned. A defensive posture was to be taken against any possible attack against northern Australia from the Merauke-Torres Strait area.¹¹⁵ By now, as in World War I, Australia was facing acute manpower problems from maintaining an Army of twelve divisions - a far larger number in proportion to population than Britain, America or Japan. Battle casualties and a high rate of tropical disease, particularly malaria and dysentry that had reduced the Army by the equivalent of a division.¹¹⁶The provisions of the Defence Act, preventing conscripts from serving outside Australian territory, compounded the manpower problem. Many militia units were already designated as AIF since three-quarters of their strengths were volunteers. In February 1943, an Act was passed allowing the militia to serve anywhere in the South West Pacific Area below the equator.¹¹⁷ By early 1943 the Japanese had heavily reinforced the Lae-Salamaua area and were exploiting to the south-east through Mubo to Wau, but were forced back to Mubo. In early March enemy attempts to reinforce Lae were defeated in the Battle of the Bismarck Sea.¹¹⁸ By 14 July, the 3^rd Division had cleared Mubo and then laid siege to Salamaua, held by the substantially reinforced Japanese 51^st Division. Salamaua fell on 11 September and Lae, following operations by the 7^th and 9^th Divisions to its west and east, fell on 16 September.¹¹⁹ The 7^th Division continued the offensive, moving up the Markham Valley and the Ramu River, to occupy Dumpu by 4 October. Although heavy fighting developed on Shaggy Ridge in the Finisterre Mountains to the north, Japanese resistance collapsed by the end of January 1944. Meanwhile, on 22 September, the 9^th Division had made a further landing north of Finschhafen. Bitter fighting followed, particularly for the possession of Sattelberg which did not fall until 24 November. By 8 December, the Japanese were in retreat, Sio falling on 15 January 1944.¹²⁰ The three AIF divisions were withdrawn for rest and retraining, being replaced by the 3^rd, 5^th and 11^th Militia Divisions. Allied successes opened the way for a US invasion of the Phillipines. As Australia’s national strategy was focussed on clearing Japanese forces from New Guinea, Australian forces were used to relieve the US garrisons in these territories. Due to manpower problems, the relieving Australian forces were much smaller than the US garrisons. The ensuing Australian campaigns have since been the subject of much debate. From October 1944 onwards the 3^rd Division and two independent brigades were moved to the Solomons, the 5^th Division was allotted to New Britain and the 6^thDivision to Aitape, while the 8^th Brigade continued its operations in the Madang-Sepik River area.¹²¹ Plans for 1945 committed I Corps (7^th and 9^th Divisions) to operations to the west of the American invasion of the Phillipines, to capture areas in Borneo suitable as naval and air bases for future operations, to capture and hold the Borneo oil installations and re-establish the Netherlands East Indies Government in Borneo.¹²² On 29 November, the unofficial policy of live-and-let-live between the American and Japanese forces on Bougainville was broken by the 3^rd Division offensives to the north, across the centre and to the south of the Island. These continued, against periodic strong resistance and counter-attacks by the Japanese, through the first half of 1945.¹²³ On New Britain, operations against the main Japanese positions across the Gazelle Peninsula were launched by the 5^th Division, initially from Jacquinot Bay where it arrived in early November 1944. From mid-March the Division had reduced the Japanese garrison to such an extant that operational requirements were reduced to active patrolling forward of the secured areas.¹²⁴ Meanwhile in New Guinea, the 6^th Division developed its operations eastward along the coast from Aitape and through the Torricelli Ranges towards Wewak, which was secured by the end of May; operations continued against the Japanese forces which had withdrawn into the Prince Alexander Ranges until fighting ended in August 1945.¹²⁵ Operations on Borneo commenced eight days before the fighting in Europe ended. On 1 May 1945 the 9^th Division landed at Tarakan and against heavy opposition secured the airfield. However obstinate opposition by the Japanese continued around Tarakan until the enemy withdrew on 14 June, being pursued relentlessly until the ceasefire in August.¹²⁶ The 9^th Division, on 10 June, was committed to capturing Brunei following landings at Labuan, the Muara Islands and Brunei Bluff. On 1 July, on the other side of the island, the 7^th Division landed at Balikpapan in the largest amphibious assault undertaken by the Australians. After heavy fighting, the enemy withdrew on 21 July.¹²⁷