Canberra tennis star Nick Kyrgios says Prime Minister Scott Morrison failed to acted quickly enough in response to the bushfires ravaging Australia.
The world No.29 also thinks the leader of the Liberal party could do more.
Kyrgios started a fundraising movement that has swept the sporting world when he prompted Tennis Australia to set up an exhibition match and then pledged $200 for every ace he serves to go towards the bushfire relief.
Australia's world No.1 Ash Barty, Novak Djokovic, NBA star Dirk Nowitzki and even pop star Pink have since jumped on board.
As have Tennis Australia, Cricket Australia, the NRL and AFL.
It's a response that's shocked Kyrgios, who felt sorry he hadn't acted sooner - given the bushfires started months ago.
Kyrgios has raised more than $11,000 with his booming serve - but inspired millions of dollars more.
The 24-year-old saw footage of people refusing to shake Morrison's hand when he visited a fire-ravaged Cobargo and felt it was because he hadn't made the fires a priority.
Morrison opted to go on a family holiday to Hawaii while Australia burnt.
Kyrgios called on Morrison and his government to act on climate change.
"As the leader of our country, I don't think Scott Morrison has done enough to be honest," he wrote on AthletesVoice.
"At the very least, he was far too slow to act, while people were losing their lives and families were losing their homes.
"There is nothing worse than that.
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"Right now, nothing is more important than helping these people and putting the fires out.
"So, if I could say anything to our politicians, it's imagine you're in the same position as these people who have been impacted.
"I think a lot about climate change and the impact that it's having on the environment.
"The time will come when our leaders will need to sit down and figure out what we can do to protect our environment.
"It's urgent that we find a solution."
Kyrgios said it's been tough concentrating on tennis.
Canberra's toxic air, full of smoke from the bushfires on the NSW south coast, has been a constant reminder.
But he's used his fundraising as motivation and so far he's had an unbeaten start to the summer - and banged down 56 aces in his three singles matches.
Kyrgios was moved into action by a photograph of a koala sitting on some grass, completely surrounded by fire.
"If the fires continue to burn like they have, you can only imagine the statistics we'll see at the end of the summer," he said.
"We've already lost half a billion animals, with almost two months of summer still ahead of us.
"With their homes on fire, these animals have nowhere to go.
"I saw a photo of a koala sitting on a patch of unburnt grass recently, with flames all around it. It was completely helpless.
"The saddest part is that many threatened species have been caught up in this tragedy.
"For some, we could be seeing their last days before they are gone forever."
Kyrgios revealed his passion for animal welfare had led to him adopting a vegan diet - something he's managed to make work despite travelling the world.
"I don't eat meat or dairy anymore. That's not for my health, I just don't believe in eating animals," he said.
"I tried a vegan diet a couple of years ago, but with all the travel I do, it was hard to stick to it.
"Since then I've managed to make it work and I've been vegetarian for quite a while.
"Seeing the footage of these animals suffering with the fires only reinforces why I've chosen this diet.
"When I see these terrible photos, I can't comprehend eating meat."