The brigade was established as a formation of the part-time
Militia in 1921, with the designation of the 2nd Cavalry Brigade. Based in regional
New South Wales, it was headquartered in
West Maitland and consisted of three light horse regiments – the
12th,
15th and
16th. as part of an effort to motorise or mechanise Australia's mounted forces in the early war years. The new brigade was assigned to the 1st Australian Motor Division, and was placed under the command of Brigadier W.E.H. Pascoe. At this time, each of the brigade's light horse regiments was converted into a motor regiment; such units were authorised to operate 14 scout cars and 44
Universal carriers. Following the arrival of the 1st Motor Division's headquarters in Rutherford, the 2nd Motor Brigade headquarters moved to Dungog, co-located with the 1st Motor Regiment, while the 24th Motor Regiment remained at Stroud. The 16th Motor Regiment at Newcastle temporarily came under brigade's command until it was sent to
Gympie,
Queensland, to reinforce the
1st Motor Brigade in April 1942. In May 1942, the armoured forces were restructured, and the 2nd Motor Brigade lost the 1st Motor Regiment, which became the 1st Army Tank Battalion and was reassigned to the
3rd Army Tank Brigade. Meanwhile, the 24th Motor Regiment was disbanded. Brigade headquarters moved to
Taree, where it was re-formed. With the disbandment of the
4th Motor Brigade, two of its motor regiments – the
6th and
7th – joined the 2nd Motor Brigade moving to
Kempsey and Taree respectively. Meanwhile, the 12th Motor Regiment re-joined the brigade, although it remained at Coffs Harbour until July when the 1st Motor Division's headquarters moved there, freeing up the 12th to move further south, around Kempsey, so that it could concentrate closer to brigade headquarters. This resulted in the 6th Motor Regiment moving to Taree at this time. In late 1942, the Australian government sought to raise two Militia armoured divisions – the
2nd and
3rd. These formations were to be established on the light scale, to complement the
1st Armoured Division, which had been raised as part of the
Second Australian Imperial Force. The brigade was assigned to the 2nd Armoured Division, and a significant restructure took place. The 6th Motor Regiment was converted into an armoured car regiment and became a divisional asset, while the 12th Motor Regiment also became an armoured car regiment and was transferred to the 3rd Armoured Division, and the 7th Motor Regiment was disbanded. To replace these losses, the 2nd Motor Brigade received the
15th,
17th and
20th Motor Regiments. These units moved to
Wallgrove in November 1942 as part of their concentration prior to joining the 2nd Armoured Division. In February 1943, the brigade moved to
Gherang,
Victoria, but around this time the 20th Motor Regiment was sent to Queensland to reinforce the
2nd Armoured Brigade and the 15th Motor Regiment was sent to Western Australia to join the
1st Armoured Brigade. This left just the 17th Motor Regiment and the brigade's headquarters in Victoria. The brigade did not see any active service and was disbanded at Gherang in April 1943, as part of a draw down of Australia's armoured forces that was undertaken once the threat of an invasion had passed. At this time, the Australian government decided to reallocate some of the manpower that had been tied up in the armoured divisions to other formations that would be used for jungle warfare, or to civilian industry. One of the brigade's former units, the 20th Motor Regiment, was subsequently deployed to
Merauke, in
Dutch New Guinea, as part of
Merauke Force to undertake defensive duties. In February 1945, the 20th Motor Regiment was converted into a pioneer battalion and was renamed the 20th Pioneer Battalion. Of the four companies subsequently raised, No. 3 Pioneer Company served in New Guinea before the end of the war. ==Brigade units==