The battle of Lae (4-16 September 1943) was the final stage in the Salamaua-Lae Campaign, and saw Australian troops with US support capture the last Japanese stronghold in the Huon Gulf area of New Guinea.
The attacks on Lae and Salamaua were the first stage of Operation Postern, the Markham Valley and Huon Peninsula Campaign (itself part of Operation Cartwheel, the implementation of the Elkton III plan). The Allied aim was to secure the New Guinea side of the Vitiaz Straits, between New Guinea and New Britain, as part of the campaign to neutralise the Japanese base on Rabaul.
The Allies first went onto the offensive in the Huon Gulf on 30 June 1943 when US troops landed at Nassau Bay, south of Salamaua. They then joined up with Australian troops advancing across the mountains from Wau in the west, and the combined force began a slow advance on Salamaua. General Adachi, the Japanese commander in New Guinea, decided that Salamaua was the key to his position, and committed most of his troops in the area to the battle.
On 4 September the 9th Australian Division (Major-General G.F. Wooten) landed on beaches twenty miles to the east of Lae. The Australians landed on two nearby beaches, and the only Japanese troops seen in the area ran. By the end of the day the Australians had over 2,400 men on the beach and were ready to move west.
On 5 September the US 503rd Parachute Regiment made an unopposed landing on pre-war airfield at Nadzab, twenty miles to the west of Lae. On the following day the 7th Australian Division (General Vasey) began to fly into Nadzab. Vasey had bet that his division would reach Lae first, with twenty cases of whiskey were at stake.
Wooten's men, coming from the east, had to fight their way across a series of rivers, which were running very high after heavy rainfall. They ran into Japanese resistance on 6 September at the Bunga River, about half way to Lae. The Australians advanced in two columns, with the 24th Brigade on the coast and the 26th further inland. The aim was to both capture Lae and prevent the Japanese garrison from escaping.
On 8 September the Australians advancing from the east reached the fast flowed Busu River, which was defended by the Japanese. A first attack early on 9 September was repulsed, but a second attack managed to establish a beachhead. The next three days were spent ferrying the 24th Brigade across the river, while at the same time a bridge was moved upstream to allow the 26th to cross. The two brigades were both across the Busu by the morning on 15 September.
The west weather and river crossings helped Vasey win his bet. His 25th Brigade left Nadzab on 10 September. By 14 September they had reached Heath's Plantation close to Lae, where they were replaced by the 33rd Battalion. On 15 September the Japanese were forced out of Edward's Plantation, and on the morning of 16 September the 25th Brigade entered Lae. The troops advancing from the east weren't far behind, and the 24th Brigade arrived later on the same day.
By then the Japanese had decided that the Lae/ Salamaua area could no longer be defended, and wanted to save the men for more important battles further north. Salamaua had been abandoned first, after the garrison was ordered to pull back to Lae on 8 September. Soon afterwards Adachi decided to pull out of Lae. The first part of the garrison left on 11 September. The Salamaua garrison reached Lae on 14 and by the end of 15 September both forces were on their way north. The later stages of the Australian advance thus encountered delaying forces. Around 9,000 Japanese troops began the march north, and 8,400 eventually reached the north coast of the Huon Peninsula. Not all of the survivors were fit for further combat, but many did play a part in the Huon Peninsula campaign.
After the fall of Lae the Allied forces split in two. The 7th Division turned back to the west and advanced up the Markham Valley, hoping to eventually head across the Finisterre Range to reach the coast behind the Japanese strongholds on the Huon Peninsula. The 9th Division moved east along the coast, heading for Finschhafen at the tip of the Huon Peninsula. The Japanese put up fierce resistance to both of these advances, and the two prongs didn't join up again until April 1944.