The ANZACs in T2k

[StainlessSteelCynic]

Well we actually do have some minor experience building tanks - in WW2. The Sentinel medium tank was designed and built in Australia when it looked like our supply of armoured vehicles from Great Britain was in jeopardy. It was a good vehicle comparing favourably with contemporary British & American designs (although with a poor turret layout for the crew) but rendered unnecessary by the availability of mass supply of tanks from the USA.
Plus there was local manufacture of Australian variants of the Universal Carrier as well as a local design, the Dingo armoured car and some armoured truck modifications.

Another item that sparked some interest with the T2k alternate timeline of Merc: 2000, an Australian company acquired the rights to the Shorland armoured car. This was in 1996 so not particularly useful for T2k timelines.
Plus we designed and implemented an upgrade for the M113 vehicles in service (to AS4 standard).

So all in all, we have the industry and the technical skills to build armoured vehicles including tanks but there is no "national need" for us to build certain vehicles e.g. tanks.
Obviously for T2k everything depends on the timeline being used but I would expect that (considering we had a Land Rover production facility in Australia for several decades supplying vehicles to the military), we would probably look at some sort of armoured car variant of the Landie at the very least. I don't think national need would extend to tanks but it's not beyond the realms of possibility.

EDIT: meant to also mention that the ASLAV design is based on the Canadian LAV design which in turn was based on the Swiss MOWAG Piranha vehicle. The Piranha in 4x4, 6x6 and 8x8 configurations has been available since the 1970s so if you tweaked the details, we could have acquired some sort of ASLAV in the 1980s.