If I was an aggressor I would simply plan to take out Western Australia (restrict action in the East to diversionary activity), secure the ports, airports, mine sites, offshore assets, grain supplies, cattle ranches and Bob's your Uncle.
it isn't exactly easy and chances are we would know you were oming and you would be sitting on the bottom of on of the various seas you would use in your approach.
Leave the East to slowly wither and die. I would love to see a land assault across the Nullabor by Australia's Eastern deployed forces, the M1A2's would run out of petrol simply because currently the government doesn't have the supply chain to keep feeding those gas turbines?
i think ours run on diesel and we can transport them by air train and truck so they don't have to drive, that is in the unlikely case that a substantial force makes it to the Australian mainland. small scale sf raids more likely but we can deal with them.
this is a two edged sword. imagine an attacking force gets to the Australian west coast but where to then? they cant just sit there indefinitely
One of the best ways to deter such agression is a strong submarine fleet, the enemy simply doesn't know where the boats are allowing for endless deception scenarios to keep the enemies Frigates / Amphib asets tied up indefinitely. The other is a strong airforce, however I doubt Aussie has the means in place to adequately defend the air bases from ground launched surprise SF attacks (no dedicated RAAF Reg?).
it is unlikely to be a surprise and we have the adgies... Airfield Defence Guards: Royal Australian Air Force : Royal Australian Air Forcehttp://en.wikipedia.org/wiki/Airfield_Defence_Guards
One of the biggest bullets the country needs to bite is that of manpower costs, in an all volunteer army they eat up one third of the defence budget, so any increases in hull numbers will have a huge knock-on effect on the cost of manning. We always hear about the cost of vessel's, airframes and tanks, but very little attention is given to addressing manning increases. 12- subs and a much needed additional AeW asset will result in the need for increased manning. 12 -subs in effect means the submarine branch will end up being one of the largest operational arms of the Navy, extremely specialised and not to everyone's taste, it's one of the hardest branches to recruit for. No one as yet appears to have come up with a credible plan as to how the subs will be sustained (recruiting, training & manning).
im sure someone somewhere has a plan or is making one.
As tension in the region rises Aussie will have to increase defence spending, possibly to the same level as a country like Singapore - 4%+ of GDP.
and you think the aus gov wouldn't respond to the tension? unfortunately the government these days lack foresight and focus on the here and now but im sure they would react if neighbors became more aggressive