Although their troops had been steadily advancing south since the start of the campaign, Savige and Bridgeford correctly believed that the Japanese had thus far only been employing delaying tactics. They anticipated that the hard fight would come when the Australians reached the Hari River. The Japanese would try to hold the river and protect the large garden areas around Monoitu, Taitai and Hari. Information from prisoners and captured documents identified the force opposing the Australian 7th Brigade around the Puriata River as the Japanese 13th Infantry Regiment, thought to be 850 strong. The regiment's 1st and 2nd Battalions were concentrated in the Makapeka–Horinu–Rumiki area, around the Old Government Road, while the 3rd Battalion was concentrated on the Buin Road around Tokinotu and Hiru Hiru. Further to the southeast, the Japanese 23rd Infantry Regiment, about a thousand strong, was located along the Buin Road between the Hongorai and Mibo Rivers, where it could either quickly reinforce the 13th Infantry Regiment or oppose a potential landing along the coast. Artillery and engineers supported both regiments. All told, Bridgeford considered there were about 3000 Japanese between the Puriata and Mibo Rivers.

The stiffening resistance met by the Australian 25th Battalion from the Japanese 3rd Battalion, 13th Infantry Regiment, after crossing the Puraita River was taken as further evidence of the Japanese intention to contest the Australian crossing of the Hongorai. So too was a prisoner statement that if the Australian advance became too serious, a force – possibly the 45th Infantry Regiment from Kieta – could be sent across the mountains to attack the Australian rear. Bridgeford considered that the Japanese were preparing to fight their main battle between the Hongorai and Hari Rivers. Cautious, he thought that moving beyond the Hongorai before he had built up a strong strike force would be unwise. Savige gave him permission to bring forward to Toko heavy artillery and tanks recently arrived in Torokina. This decision proved crucial.