Rather than compare the month-on-month seasonally adjusted results (which are extremely volatile) it is interesting to look at the last couple of years for each state and where that sits in terms of the long-run history for the jurisdiction.
In that context, Victoria appears an outlier. While well down on its 2009-2011 record-breaking splurge, the trend number of monthly approvals is still above the long-run average. This is odd, given the broader commentary that suggests the Victorian dwelling market is over-supplied.
The ABS does not produce a trend and seasonally adjusted series for the Northern Territory or the Australian Capital Territory.
Update: I have been looking at Table 20 from the ABS, which reports on the types of dwellings that were approved each month. The tables appears to be only available in the original series, so I have undertaken my own seasonal adjustment. Note that semi-detached includes terrace houses and town-houses; and apartments includes flats and units.