Scott Morrison has blasted Israel Folau's "appallingly insensitive" comments, while Opposition Leader Anthony Albanese called the sacked Wallabies star "reprehensible".
Folau claimed the bushfires crippling Australia were God's punishment for legalising abortion and same-sex marriage.
Dumped by Rugby Australia after claiming homosexuals would go to hell, Folau has doubled down in a video sermon posted to the Truth of Jesus Christ Church Sydney.
The prime minister is also a practising Christian but stressed Folau's comments were not representative of his community.
"The thoughts and prayers, let me stress, from Christians, are very much with those who are suffering under the terrible burden of fire," Mr Morrison told reporters in Adelaide on Monday.
"I thought these were appallingly insensitive comments.
"If people don't have something sensible and helpful to say, can you just keep it to yourself."
Mr Albanese said Folau had a history of making provocative comments and that it was incumbent on people with "common-sense" to reject them.
"His comments are in line with some of his other comments which are pretty reprehensible," Mr Albanese told Sky News on Monday.
"It would good if people thought before they spoke. These comments certainly won't bring anything positive or constructive to the debate."
Nationals backbencher Barnaby Joyce said it was pointless to engage with Folau.
"He throws rocks at us so he feels good, we throw rocks back at him so we feel good ... but not one of those actions is making a sandwich for a person fighting the fires," Mr Joyce told the Seven Network.
"Not one of those actions is actually in a fire truck trying to stop these fires. Israel can concentrate on what he wants to say and I don't really care and we'll concentrate on the fire."
During the 10-minute sermon, Folau said the timing of the bushfire crisis, which has left six Australians dead, was no coincidence, but rather a taste of God's judgment.
"I've been looking around at the events that's been happening in Australia, this past couple of weeks, with all the natural disasters, the bushfires and the droughts," he said.
Folau then linked a Bible passage to the twin disasters of bushfire and drought and, in turn, the legalising of same-sex marriage and abortion.
"The events that have happened here in Australia, in the last couple of years - God's word says for a man and a woman to be together ... they've come and changed this law," he said.
"Abortion, it's okay now to murder, kill infants, unborn children."
Folau said he believed the scripture was talking to Australia.
"God is speaking to you guys. Australia you need to repent and take these laws and turn it back to what is right."
The controversy which saw Folau's $4 million contract torn up in April was the dual international's second run-in with Rugby Australia after being reprimanded for a similar social media post in 2018.
Australian Associated Press