On 17 January, despite reservations about the state of the brigade's fitness, a brigade group based on the 53rd Brigade (under the command of Brigadier Cecil Duke) had arrived in the Ayer Hitam area of Johor and elements were attached to the 11th Indian Infantry Division in III Indian Corps to reinforce the defences from Batu Pahat to Yong Peng. 6RNR was deployed around to the west to defend a tactically important defile and causeway between Bukit Pelandok (south of the pass) and Bukit Belah (to the north). 2CR relieved the garrison at Batu Pahat, around southwest of Ayer Hitam. Both battalions were also assigned to patrolling the roads against Japanese infiltration. Japanese patrols were soon encountered by 2CR southwest of Batu Pahat, and 6RNR (near Bukit Pelandok) was attacked from the air. 5RNR was allocated to Westforce (an "ad hoc" multi-national force assembled under the command of Australian Major-General Gordon Bennett) to relieve the 2/19th Australian Battalion at Jemaluang. Several Australian officers were to remain behind and aid 5RNR in taking over their positions and one said: