Thunberg finished, "That's what has to change. Now."
Her tweet has received more than 47,000 comments and 148,000 likes.
The comments come after Scott Morrison defended his government's response to the bushfire crisis despite major backlash over political inaction and his recent family holiday to Hawaii.
Mr Morrison did, however, acknowledge the need for real action on climate change across all state and federal levels.
“There is no disagreement and there has not been any denial of this critical factor, either by the federal government or any state or territory government,” he wrote in The Daily Telegraph. “But to suggest that increasing Australia’s climate targets would have prevented these fires or extreme weather events, in Australia or anywhere else, is simply false.”