I don't think the AUD is to blame. The currency majors I follow have all decreased in value compared to the USD in recent weeks.So far,as soon as the economy or markets sneeze,we go down vs USD
I think it is more to do with interest rate expectations, which, in my mind, is the primary driver in setting the rate between different currencies.
So, rather than the AUD and other majors going down, investors / speculators are saying that they expect interest rates to rise in the US quite a while before any where else.
After saying that, I've got no idea what is happening with NZD. Yes, its gone down in value compared to the USD, but NZ interest rates are already rising. Maybe it is just that. Expectation of interest rate changes which is the driver.
KH