Australia has seasonal bush fires. ("Wildfires" in American English)
For several years in a row, there have been arrests for arson. It is widely accepted that a certain number of bush fires are deliberately lit.
Last year was the most devastating. Many more hectares burned than usual. Much more smoke in capital cities than usual. There was a shortage smoke filtering N95 masks - they were all bought up by Chinese agents. This paragraph is not speculation, it was all reported by the Australian MSM.
No news of arrest for foreign agents so far.