With the eyes of the world watching, Scott Morrison has hit out at the "internal and global critics" of his Government's climate change policies.
This week, he's copped criticism from scientists and many in the world of social media for skipping a special climate conference in New York on Monday.
However, in his address to the United Nations overnight, he accused climate activists and the media of spreading "completely false" information about Australia's action on climate change.
The Prime Minister focused on Australia's practical actions on environmental challenges, such as plastics in the oceans, waste management and fishing.
And he said the country was committed to its target of cutting emissions by 26-28 per cent below 2005 levels by 2030, describing that as a "credible, fair, responsible and achievable contribution".
"Australia's internal … and global critics on climate change willingly overlook or, perhaps, ignore our achievements, as the facts simply don't fit the narrative that they wish to project about our contribution," Mr Morrison told the general assembly.
Ahead of the speech, the Prime Minister said Pacific leaders he spoke with were often surprised to learn what Australia was doing on climate.
"Oftentimes the criticisms that have been made about Australia are completely false," he told reporters in New York.
"Where do they get their information from? Who knows? Maybe they read it, maybe they read it.
"Australia's got nothing to apologise for."
He also appeared to make a direct reference to Swedish teenage climate change activist Greta Thunberg's highly-publicised address on Monday.
"We should let our kids be kids — teenagers be teenagers," Mr Morrison said.
"We must respect and harness the passion and aspiration of our younger generations, rather than allow others to compound or, worse, facelessly exploit their anxiety for their own agendas."
However, he also revealed he received many letters from children concerned about their future — adding that he welcomed "their passion, especially when it comes to the environment".
Asked if his criticism of the media was akin to calling it "fake news" — a favourite insult of US President Donald Trump — he replied: "I'm not saying that. All I'm saying is when I've spoken to them, they've been surprised to learn about the facts about what Australia has been doing."
He told the UN that Australia would beat its 2020 Kyoto targets and claimed it would also meet its 2030 Paris pledge.
Earlier, Mr Morrison was more bullish, saying Australia "won't just meet our 2030 commitments, I suspect we will hopefully be able to do better than that".
Environment department figures show Australia's emissions have risen since 2014. Under the Paris agreement, all countries are expected to update their pledges to cut emissions at the 2020 climate conference in Glasgow.
But Mr Morrison indicated that at this stage, Australia was unlikely to do so.
"We have our commitments, and we're sticking to those commitments," he said.
Mr Morrison also confirmed to the UN that Australia wouldn't contribute anymore to the global Green Climate Fund.
The May Budget papers said Australia made its last payment into the fund in December 2018.
Instead, Australia is redirecting A$500 million of its aid money to help Pacific Island nations become more resilient in the face of the effects of climate change.
"I'm not writing a $500 million cheque to the UN, I won't be doing that. There's no way I'm going to do that to Australian taxpayers," Mr Morrison told reporters.