In Tasmania we have a similar process, Forestry operators obliterate our native forests, then burn what's left.
This goes on for 9 months of the year until it's simply too hot and dry to burn.
Once they have burned the forest residue with incendiaries (the same formula as Napalm is used) they replace the once diverse forest with monoculture plantations attracting insect swarms.
Then the spraying starts; as often as fortnightly. One chemical commonly used is Atrazine, banned in Europe where it's manufactured and severely restricted in the US. In the US where Atrazine use is allowed, several buffer zones of vegetation must be planted to filter ground water and runoff before it gets to streams, here there are no such requirements. It's becoming increasingly more difficult to keep ahead of the insects as they become resistant to the chemical sprays. The residue of chemicals washes in to our watercourses, Australian standards allow 400 times the levels allowed in the US. In parts of Europe, Atrazine still contaminates ground water despite being banned from use for 15 years.
They are destroying our biodiversity and poisoning our air and water. I suspect a lot of what you see in Victoria isn't hazard reduction burning, but more likely regeneration burns, hazard reduction burns are usually done at the end of spring before the summer heat.
You should take action, for if you don't it will only get worse, don't put up with it.