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 the Japanese lines, the Mubo area, at features known to the Allies as "The Pimple" and "Green Hill" during the Battle of Mubo.
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.
Later in May, the 2/7th repelled a number of strong Japanese counter-attacks.

At the same time as the fighting around Mubo the Australian 24th Infantry Battalion, which had been defending the Wampit Valley in an effort to prevent Japanese movement into the area from Bulolo, detached several platoons to reinforce the 2/3rd Independent Company.
During the month of May, they were heavily engaged in patrolling the 3rd Division's northern flank, around the Markham River, and the area around Missim.
One patrol succeeded in reaching the mouth of the Bituang River, to the north of Salamaua.
On 11 May, the 2/3rd sent patrols to Bobdubi Ridge and subsequently occupied it, having found that the Japanese had abandoned it; long range exchanges of fire with Japanese troops on Komiatum Ridge followed, and a full scale Japanese attack followed, supported with artillery, pushing the commandos from the ridge on 14 May. This was followed by heavy air attacks on Australian positions on 15 May. Elsewhere, in an effort to defend the approaches to Wau, troops from the 2/7th Infantry established themselves in a defensive position around Lababia Ridge, which was located about 2 kilometres (1.2 mi) south-west of Mubo, and throughout late June, the Australians fought a defensive action along the ridge.

Between 30 June and 19 August, the Australian 15th Brigade cleared Bobdubi Ridge, in order to relieve pressure on the forces around Mubo, and gain control of the Komiatum Track, thereby cutting off the Japanese forces in front of Mubo and disrupting Japanese efforts to resupply them.
This was undertaken in conjunction with the landing of US troops around Nassau Bay, while the 17th Bridge would launch a final effort around Mubo.
The operation was opened in late June with an assault by the inexperienced 58th/59th Infantry Battalion, and included hand-to-hand combat; meanwhile, on the northern Australian flank the 24th Infantry Battalion set up ambushes and clashed with small groups of Japanese along the Malolo Track.
During the initial attack on Bobdubi, the Japanese forces holding it equated to about one company from the 115th Infantry Regiment, but over the course of several days, these were reinforced by about 200 troops from the 66th Infantry Regiment, and then a battalion of the 80th Infantry, which was hurriedly dispatched from Lae.

In early July, the 2/3rd Independent Company launched an attack against "Ambush Knoll", a feature which controlled Bobdubi Ridge, and captured it.
By capturing the knoll, the 2/3rd threatened the Japanese supply lines to Mubo and Salamaua and because of this it forced them to launch a number of fierce counterattacks in an attempt to retake it.
These counterattacks occurred over the course of the following three days and four nights, however, the platoon from the 2/3rd, consisting of only 52 men, managed to hold the knoll.
Later in the month, the 2/3rd attacked the Japanese around the "Timbered Knoll", launching a successful flanking attack which pushed the Japanese off the position.

At the end of July, the 2/6th Infantry Battalion put in a company-level attack on the Japanese flank and managed to secure one of the feature's in front of Ambush Knoll.
Meanwhile, the 58th/59th attacked around a position dubbed "Old Vickers".
Heavily supported with indirect fire and machine-guns, the attack was successful and, the Japanese abandoned Bobdubi Ridge.
The fighting over the six weeks to that point had been heavy, with Japanese losses at the hands of the 15th Brigade being estimated at around 400 killed, against 46 killed and 152 wounded for the Australia
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 the Japanese lines, the Mubo area, at features known to the Allies as "The Pimple" and "Green Hill" during the Battle of Mubo. 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. Later in May, the 2/7th repelled a number of strong Japanese counter-attacks.
At the same time as the fighting around Mubo the Australian 24th Infantry Battalion, which had been defending the Wampit Valley in an effort to prevent Japanese movement into the area from Bulolo, detached several platoons to reinforce the 2/3rd Independent Company. During the month of May, they were heavily engaged in patrolling the 3rd Division's northern flank, around the Markham River, and the area around Missim. One patrol succeeded in reaching the mouth of the Bituang River, to the north of Salamaua. On 11 May, the 2/3rd sent patrols to Bobdubi Ridge and subsequently occupied it, having found that the Japanese had abandoned it; long range exchanges of fire with Japanese troops on Komiatum Ridge followed, and a full scale Japanese attack followed, supported with artillery, pushing the commandos from the ridge on 14 May. This was followed by heavy air attacks on Australian positions on 15 May. Elsewhere, in an effort to defend the approaches to Wau, troops from the 2/7th Infantry established themselves in a defensive position around Lababia Ridge, which was located about 2 kilometres (1.2 mi) south-west of Mubo, and throughout late June, the Australians fought a defensive action along the ridge.
Between 30 June and 19 August, the Australian 15th Brigade cleared Bobdubi Ridge, in order to relieve pressure on the forces around Mubo, and gain control of the Komiatum Track, thereby cutting off the Japanese forces in front of Mubo and disrupting Japanese efforts to resupply them. This was undertaken in conjunction with the landing of US troops around Nassau Bay, while the 17th Bridge would launch a final effort around Mubo. The operation was opened in late June with an assault by the inexperienced 58th/59th Infantry Battalion, and included hand-to-hand combat; meanwhile, on the northern Australian flank the 24th Infantry Battalion set up ambushes and clashed with small groups of Japanese along the Malolo Track. During the initial attack on Bobdubi, the Japanese forces holding it equated to about one company from the 115th Infantry Regiment, but over the course of several days, these were reinforced by about 200 troops from the 66th Infantry Regiment, and then a battalion of the 80th Infantry, which was hurriedly dispatched from Lae.
In early July, the 2/3rd Independent Company launched an attack against "Ambush Knoll", a feature which controlled Bobdubi Ridge, and captured it. By capturing the knoll, the 2/3rd threatened the Japanese supply lines to Mubo and Salamaua and because of this it forced them to launch a number of fierce counterattacks in an attempt to retake it. These counterattacks occurred over the course of the following three days and four nights, however, the platoon from the 2/3rd, consisting of only 52 men, managed to hold the knoll. Later in the month, the 2/3rd attacked the Japanese around the "Timbered Knoll", launching a successful flanking attack which pushed the Japanese off the position.
At the end of July, the 2/6th Infantry Battalion put in a company-level attack on the Japanese flank and managed to secure one of the feature's in front of Ambush Knoll. Meanwhile, the 58th/59th attacked around a position dubbed "Old Vickers". Heavily supported with indirect fire and machine-guns, the attack was successful and, the Japanese abandoned Bobdubi Ridge. The fighting over the six weeks to that point had been heavy, with Japanese losses at the hands of the 15th Brigade being estimated at around 400 killed, against 46 killed and 152 wounded for the Australia
Battle of Bobdubi