There were two lengthy stoppages, the first coming after less than five minutes in when Jake Kostecki clipped the wall at Turn 12.
To that point it was Will Davison leading the way, the Dick Johnson Racing driver having clocked a 1m11.019s right before the stoppage.
When the session resumed Davison and Cam Waters quickly dropped into the 1m10s, right before Shane van Gisbergen jumped them both with a 1m10.669s.
The next stoppage came at the mid-point of the session, this time triggered by Todd Hazelwood, who wound up buried in the tyres at the last corner.
One the session went green again van Gisbergen was able to go even faster, lowering the benchmark to an unbeatable 1m10.404s.
While that put him three-tenths clear of the field, the Kiwi was left a little concerned about his Top 10 Shootout simulation.
"It means nothing," he said. "The shootout is still to come.
"We did a Shootout run on my second lap, so we had the tyres a bit up, and I couldn't turn the tyre on, so that's a bit of a worry."
Chaz Mostert ended up best of the rest in second while Brodie Kostecki managed to set the third fastest time on the second lap of his final run.
Davison ended up fourth fastest ahead of James Courtney, David Reynolds and Andre Heimgartner.
Thomas Randle was eighth, Cam Waters ninth and Anton De Pasquale the final driver to book a Shootout spot in 10th.
Scott Pye was the driver left on the bubble of the Top 10, the Team 18 driver set to start 11th after ending up three-hundredths behind De Pasquale.
The first five rows of the grid will be determined by the Top 10 Shootout, which kicks off at 1:05pm local time.
