Not Targa Tas, but gravel rallying is alot more fun/skillfull/safe anyway! And besides, even the Australian Rally Championship doesn't have ridiculous $5000 entry fees like targa does...
The closest thing you'll get to that is what's known as a Touring Road Event with Speed Subsections...
In QLD we've probably got the best one in Australia called the QLD challenge... Its as close to a Targa event as you'll get, and the entry fee is just over $100, with very little safety requirements...
The QLD Challenge does a couple of laps of the IWMAC at Willowbank, then does laps around the Gatton QUT Campus, then a mad dash down the side of the Toowoomba range, then sprints through the Wivenhoe dam complex... All in all a pretty mad day!
checkout
http://www.queenslandchallenge.com/ for all the info...
Traditionally i've entered either my gravel or tarmac rally car, but this year i'm probably gonna enter the Commodore... Be interesting to see how we go in the AWD class against the Subabishi's!