This is completely untrue. The extent of sub-prime mortgages isn't the same, but it exists nonetheless. As does the existence of RBMS, which the government continues to purchase from the banks.
All of that looks over the fact that the big 4 banks in Australia are massively overexposed to residential mortgages and small business loans underpinned by residential property. In some ways it's worse than the USA because the mortgages are still on the books rather than being sold off into the secondary market.
The differences between the Irish housing bubble and the Australian housing bubble are actually much less. So you're right to say that there the parallells between the USA and Australia are less, but the parallells between Ireland and Australia are few. Ireland has full-recourse mortgages like Australia. Ireland had a massive overinvestment in property, like Australia. Ireland had high immigration, like Australia.
As I've said elsewhere in this thread, I don't think there is ever a time when you take your eyes off the negative.