Who exactly would have capability and resources to mount an invasion and then supply the necessary force to occupy a territory the size of Australia.

China.

Also worth noting that the force needed to occupy a country is mainly proportional to the population.

Indonesia is right next door and outnumber us 10 to 1.

India and China are also reasonably close.

The only thing we want is to beat you at cricket.

- India.

A blue water Navy, not proximity, is what is required to invade and control Australia. India and Indonesia are a non-starter given that prerequisite, and China is probably 10-20 years away from being able to accomplish this (if they chose to do it). Plus the Chinese are more concerned with the South China Sea and regional naval superiority when compared to invading continents.

Also, Pine Gap. All of the China is coming and the US is going to leave us hanging out to dry hubbub conveniently ignores this fact.

Current navy size seems less relevant than what it could be if they were planning to invade Australia. If I decided to invade an island nation my first step would be to build enough boats.

No invasion would be needed.

All thats needed is to get several thousand armed people to take control of Canberra, Sydney and Melbourne parliament and hold all the politicians under lock and key. And whilst Australia is too stunned to work out what has just happened, land ships and troops in Sydney then Melbourne.

There you have it - control of Australia.

All we need to do is put a bell on the cat!

Several thousand armed people acting in concert without detection?

The Australian military would also still exist even if such a thing could be done.

Not to mention that then landing ships in Sydney and Melbourne would not be allowed by the US.

The Australian populace wouldn't just take it either.

The US may decide that we are past our best before date and choose to cut and run rather than take on a land war in Asia.

>>> Several thousand armed people acting in concert without detection?

You haven't heard of tourists?

You just described a (shitty and likely to fail) invasion.

China is a very real threat to Australia. They are already unhappy about how close we are to the US, our freedom of navigation routes through the South China Sea and our perceived anti-China rhetoric around national security.

And just to show you that they aren't messing around. They just funded the development of a port in Vanuatu which many have suspected as being suitable for future naval purposes:

https://www.smh.com.au/politics/federal/the-great-wharf-from...

I think this would be a huge miscalculation for China. First it would enrage Western governments, especially the US and UK. Second, I'm not completely convinced China would win. Australia is a very large country, with a population that has basically nothing in common with the Chinese. It would be very difficult to stop guerilla warfare even if they controlled the cities. Plus, China knows how ridiculously complicated this kind of stuff is to win in the long run. Look at Vietnam and Korea. I think China would be more likely to attempt stronger alliances now that US leadership is basically gone for 2-6 more years.

If China is a threat to Australia, maybe we shouldn't have sold them the port of Darwin...

You don't have enough money to nuke up, unless you plan a much bigger defense budget.

Really ? Australia has the 13th highest GDP in the world.

Higher than Israel, Pakistan and North Korea which all have them.

They can't really afford them, either.

You'll also need missiles capable of hitting your adversary, and you won't find much help building them cheaply.