The battle of Wareo (26 November-10 December 1943) saw the Australians capture the last major Japanese stronghold in the vicinity of Finschhafen, at the eastern tip of the Huon Peninsula, firmly securing their beachhead and clearing the way for an advance further north around the coast. The Australians had landed north of Finschhafen on 22 September, and captured the port on 2 October. The Japanese responded with a major counterattack, beginning on 16 October, and for a few days split the narrow Australian beachhead in two. The attack soon ran out of steam and on 19 October the Japanese were forced back from the coast.
The Australians now went onto the offensive. Their first target was Sattelberg, west of their main landing beach and north-west of Finschhafen. This was captured after a battle that lasted from 29 October until 25 November, and that removed the main Japanese threat to the Australian beachhead.
The next Australian move was a two-pronged assault on Wareo, the next Japanese position to the north of Sattelberg and their last major inland possession in the Finschhafen area. On 26 November the 24th Brigade was ordered to capture Gusika then move west towards Wareo, while the 26th Brigade attacked from Sattelberg. Hopefully the two forces would be able to join up at Sattelberg.
The advance began on 26 November with an attack by the 2/32nd, aimed at clearing the way for the Gusika attack by improving links to an isolated Australian outpost at Pabu, between Gusika and Wareo.
The main attack on the Gusika Front began on 28 November. On the following day the 2/28th made an unopposed entry into Gusika, while the 2/32nd advanced west from Pabu. By 2 December the Australians were half way along the track to Wareo.
The 26th had a harder task. Their route took them down from Sattelberg into the Song valley, then up a steep ascent to the strongly held Japanese position at Kuanko, south of Wareo. They were able to cross the river by nightfall on 28 November. Despite the difficult terrain they were able to capture Kuanko on 1 December.
By now the Japanese had decided to pull out of Wareo. A fresh Japanese regiment was given the task of defending the coastal trail north of Gusika, to give the troops from Wareo time to escape. At the same time a series of counterattacks were launched against the Australians at Kuanko. This held the Australians up until 7 December, but on the following day they captured Wareo and on 10 December troops from the 24th and 26th Brigades met up on the trail between Wareo and Gusika.
The fighting on the coastal trail had been entrusted to the newly arrived 4th Australian Brigade. Progress was slow, and by 20 December they had only advanced ten miles. They were then relieved by the 20th Brigade, who were able to push the Japanese back. They were greatly aided by developments elsewhere. On 16 December the Americans landed at Arawe, and on 26 December they landed at Cape Gloucester, both on New Britain. This was what the Japanese presence on the eastern tip of the Huon Peninsula had been meant to prevent.
A further blow came on 2 January 1944 when the Americans landed at Saidor, west of the Japanese position on the northern coast of the Peninsula. General Adachi decided to order the survivors of the 20th and 51st Divisions to retreat west towards Madang, avoiding the new American beachhead. As a result they began to pull out of the positions in front of the advancing Australians, who were able to reach Sio on 15 January 1944. This ended the 9th Division's role for the moment, and on 21 January they were replaced by the 5th Division.