Hi
I guess the key words here are "extinguished forested fire areas" and assume that no emergency services are still active because if they were you would be breaking CASA regs - https://www.casa.gov.au/drones/rules/emergencies .
Having got my drone licence for commercial work in late September, I would want to be very confident about any fire services activities so probably refer to the Fire Services website or their app.
Cheers
Mark