From an article behind a paywall:
The ATSB said investigators only drained about 250ml of blue fuel from the main tank’s bladder when the wreckage was inspected in Darwin days later after being slung out of the swamp and then transported by road. However witnesses told the ATSB that only green fuel was available at Mount Borradaile on the morning of the crash
Can you still get green AVGAS in Australia?