Salamaua – Lae campaign The Salamaua – Lae campaign was a series of actions in the New Guinea campaign of World War II . Australian and United States forces sought to capture two major Japanese bases , one in the town of Lae , and another one at Salamaua . The campaign to take the Salamaua and Lae area began with the Australian attack on Japanese positions near Mubo , on 22 April 1943 . The campaign ended with the fall of Lae on 16 September 1943 . Background . During 1942 , the Japanese established major bases on the north coast of New Guinea , in the large town of Lae , and in Salamaua , a small administrative town and port , 35 kilometres ( 22 mi ) to the south . Salamaua was a staging post for attacks on Port Moresby , such as the Kokoda Track campaign . When the attacks failed , the Japanese turned the port into a major supply base . Logistical limitations meant that the Salamaua - Lae area could garrison only 10 , 000 Japanese personnel : 2 , 500 seamen and 7 , 500 soldiers . The defences were centred on the Okabe Detachment , a brigade - sized force from the 51st Division under Maj . Gen . Toru Okabe . In January 1943 , the Okabe Detachment was defeated in an attack on the Australian base of Wau , about 40 kilometres ( 25 mi ) away . Allied commanders turned their attention to Salamaua , which could be attacked by troops flown into Wau . This also diverted attention from Lae , which was a major objective of Operation Cartwheel , the Allied grand strategy for the South Pacific . It was decided that the Japanese would be pursued towards Salamaua by the Australian 3rd Division , which had been formed at Wau , under the command of Maj . Gen . Stanley Savige . Salamaua . Between 22 April and 29 May 1943 , the Australian 2 / 7th Infantry Battalion , at the end of a long and tenuous supply line , attacked the southern extremity of Japanese lines , the Mubo area , at features known to the Allies as " The Pimple " and " Green Hill " . While the 2 / 7th made little progress , they provided a diversion for the 2 / 3rd Independent Company , which advanced in an arc and raided Japanese positions at Bobdubi Ridge , inflicting severe losses . In May , the 2 / 7th repelled a number of strong Japanese counterattacks . At the same time as the first battle at Mubo , the Australian 24th Infantry Battalion attacked to the near south - west of Salamaua , in the Bobdubi Range , between 22 April and 29 May . This allowed other units to secure the crossing over the Francisco River , on the track to Salamaua . The Japanese Eighteenth Army commander , Lieutenant General Hatazō Adachi , sent the 66th Regiment from Finschhafen to reinforce the Okabe Detachment and launch an offensive . The 1 , 500 strong 66th attacked at Lababia Ridge , on 20 – 23 June . The battle has been described as one of the Australian Army ' s " classic engagements " of World War II . The ridge ' s only defenders were " D " Company of the 2 / 6th Battalion . The Australians relied on well - established and linked defensive positions , featuring extensive , cleared free - fire zones . These assets and the determination of " D " Company defeated the Japanese envelopment tactics . Between 30 June and 19 August , the Australian 15th Infantry Brigade cleared Bobdubi Ridge . The operation was opened with an assault by the inexperienced 58 / 59th Infantry Battalion , and included hand - to - hand combat . At the same time as the second Australian assault on Bobdubi , on 30 June – 4 July , the U . S . 162nd Regimental Combat Team made an unopposed amphibious landing at Nassau Bay and established a beachhead there . A week after the Bobdubi attack and Nassau Bay landing , the Australian 17th Brigade launched another assault on Japanese positions at Mubo . With the Allies making ground closer to Salamaua , the Japanese withdrew to avoid encirclement . Meanwhile the main body of the 162nd RCT followed a flanking route along the coast , before encountering fierce resistance at Roosevelt Ridge — named after its commander , Lieutenant Colonel Archibald Roosevelt — between 21 July and 14 August . Between 16 July and 19 August , the 42nd and 2 / 5th Infantry Battalions gained a foothold on Mt Tambu . They held on despite fierce Japanese counter - attacks . The battle turned when they were assisted by the 162nd RCT . On 23 August , Savige and the 3rd Division handed over the Salamaua operation to the Australian 5th Division under Major General Edward Milford . After Allied landings near Lae in the first week of September , Japanese forces withdrew to the north , and the 5th Division occupied Salamaua on 11 September . < br > Operation Postern . The codename for the main operations to take Lae was Operation Postern . This was a classic pincer movement , involving an amphibious assault east of the town , and an airborne landing near Nadzab , 50 kilometres ( 30 mi ) to the west . Lae . On 4 September , the Australian 9th Division , under Major General George Wootten , landed east of Lae , on " Red Beach " and " Yellow Beach " , beginning an attempt to encircle Japanese forces in the town . Five U . S . Navy destroyers provided artillery support . The landings were not opposed by land forces but were attacked by Japanese bombers , who killed about 100 Allied naval and army personnel . The 9th Division faced formidable natural barriers in the form of rivers swollen by recent rain . They came to a halt at the Busu River , which could not be bridged for two reasons : the 9th lacked heavy equipment , and the far bank was occupied by Japanese soldiers . On 9 September , the 2 / 28th Infantry Battalion led an attack and secured a bridgehead after fierce fighting . Nadzab . The following day , the U . S . 503rd Parachute Infantry Regiment , together with two gun crews from the Australian 2 / 4th Field Regiment — who had received a crash course in the use of parachutes — and their cut - down 25 - pounder artillery pieces , made an unopposed parachute drop at Nadzab , just west of Lae . The airborne forces secured Nadzab Airfield , so that the Australian 7th Division , under Major General George Vasey , could be flown in , to cut off any possible Japanese retreat into the Markham Valley . The 7th Division suffered its worst casualties of the campaign on 7 September , as they were boarding planes at Port Moresby : a B - 24 Liberator bomber crashed while taking off , hitting five trucks carrying members of the 2 / 33rd Infantry Battalion : 60 died and 92 were injured . On 11 September , the 7th Division ' s 25th Infantry Brigade engaged about 200 Japanese soldiers entrenched at Jensen ' s Plantation in a firefight , at a range of 30 m ( 50 feet ) , with the 2 / 24th Field Regiment providing artillery support . After defeating them and killing 33 enemy soldiers , the 25th Infantry Brigade engaged and defeated a larger Japanese force at Heath ' s Plantation , killing 312 Japanese soldiers . It was at Heath ' s Plantation that Private Richard Kelliher won the Victoria Cross , the highest award for gallantry in the British Commonwealth . The 25th Infantry Brigade entered Lae on 15 September , just before the 9th Division ' s 24th Infantry Brigade . The two units linked up that day . Aftermath . While the fall of Lae was clearly a victory for the Allies , and it was achieved more quickly and at lower cost than anticipated , a significant proportion of the Japanese garrison had escaped through the Saruwaged Range , to the north of Lae , and would have to be fought again elsewhere . The Huon Peninsula campaign was the result . Salamaua was not developed as a base . The Australian I Corps commander , Lt Gen . Sir Edmund Herring , visited Salamaua by PT boat on 14 September 1943 , three days after its capture , and found little more than bomb craters and corrugated iron . He recommended cancelling the development of Salamaua and concentrating all available resources on Lae . The base that had originally been envisaged now looked like a waste of effort , because Salamaua was a poor site for a port or airbase . However , in drawing the Japanese attention away from Lae at a critical time , the assault on Salamaua had already served its purpose . Lae was transformed into two bases : the Australian Lae Base Sub Area and the U . S . " Base E " . Herring combined the two as the Lae Fortress , under Milford . Because General Thomas Blamey , as commander of the Allied New Guinea Force , had launched Postern before the logistical preparations were complete , most of the units needed to operate the base were not yet available . The importance of Lae as a port was to supply the airbase at Nadzab , but this was compromised because the Markham Valley Road was found to be in poor condition . In order to expedite the development of Nadzab , minimal efforts were made to repair it , and heavy military traffic bound for Nadzab was permitted to use it . The road was closed following heavy rains on 7 October and did not reopen until December . Until then , Nadzab had to be supplied by air , and its development was slow because heavy engineer units could not get through .