Here is the article from the Australian I was referring to regarding the defence white paper.
I was going off 2013 figures for Defence spending, recent acquisitions (Canberra class LHD etc) have driven up Australian defence spending 16% since then so my apologies there.
To fill the gaps in our defence force sufficiently and cost effectively entry level soldier pay would have to be taken below minimum wage in order to expand our forces significantly enough. I don't think that would fly politically especially with army vet Jacquie Lambie holding the balance of power.
They have more than 7 more modern combat capable warships (they have at least 13 capable of modern missile based ship to ship combat possibly more), a modern or even modernized missile corvette can still sink a far larger target.
I agree that military procurement is very rarely done in an on time manner, but it ultimately shows that their goals would outstrip not only the navy we have now but the navy we plan to have (replacement for Anzac Class, Hobart Class AW Destroyers).
I will admit that the 5 times current spending is overstated (however in an economy with a declining GDP its hardly impossible), however 3 times is hardly outside the realm of possibility especially when compared with other examples.
The Israeli defence budget as you stated is 5.4% of GDP, but look at the force they have for that money, for only $18.6 billion USD a year.
Their combat capable air force is more than 3 times the size of ours just for a start, their standing army is more than 4.5 times the size of ours all for less than 60% of our military budget.
For the costs involved in expanding our own much smaller and more expensive military I can only imagine how high they would be. The head of the Australian Strategic Policy Institute, Peter Jennings, has estimated that, without a credible US alliance, Australia would need to double its defence spending from 2 per cent of GDP a year to 4 per cent, an extra $32 billion a year in today’s dollars.
Kim Beazley for the Australian Strategic Policy Institute wrote that the budget for Defence force acquisitions may have to double or trouble should Donald Trump choose to completely remove the United States from Asia, this is more or less the same thing as Australia abandoning Anzus. I would link the article but its behind the horrible Australian paywall.