As everyone is aware, spending growth is strongest in Western Australia, as resource producers seek to put in place more capacity and the income gains from the boom are partly spent. But the differences in spending overstate the differences in actual economic performance between the regions.
Not all the demand generated in Western Australia is being supplied from there: some of it is being supplied from the rest of the country, and some of it from outside Australia. It is partly for that reason, presumably, that the differences in employment growth and unemployment trends across states are much smaller than the differences in spending.