Prime Minister Tony Abbott says he deplores Russia's involvement in the Ukraine conflict but still treated Vladimir Putin with respect at the G20 because he was a guest.
Mr Abbott was asked about his relationship with the Russian president after unveiling the summit's official communique on Sunday.
He said the G20 provided an opportunity to speak candidly with Mr Putin about their differences, particularly over the conflict in eastern Ukraine and the downing of flight MH17 over the region.
"I don't particularly approve, in fact I utterly deplore, what seems to be happening in eastern Ukraine," Mr Abbott told reporters.
"I demand that Russia fully cooperate with the investigation, the criminal investigation of the downing of MH17 - one of the most terrible atrocities of recent times."
Mr Abbott said he and other leaders had "very robust discussions" with Mr Putin about Russia's involvement in Ukraine.
It followed on from "very robust discussions" during the APEC summit in Beijing last week as well, he said.
But Mr Abbott said Mr Putin, who was the first major leader to leave the G20 early on Sunday afternoon, was a guest in Australia.
"President Putin is a member of the G20 and I was happy to treat him with respect and courtesy while he was here in Australia," he said.
Mr Abbott made headlines last month after threatening to "shirt front" Mr Putin over Russia's alleged role in the MH17 disaster.
Earlier on Sunday, Australia, Japan and the United States jointly condemned Russia over the Ukraine crisis.
The three nations also vowed to bring to justice those responsible for the downing of MH17.
British Prime Minister David Cameron said Russia would suffer if it did not help stop the conflict in Ukraine.
"Russia needs to know that there is a real unitive purpose between America and the European Union in making sure we don't have some permanent frozen conflict on the continent of Europe," he told reporters in Brisbane.
"If that is to happen I don't think the relationship between Russia on one hand and Britain and America on the other hand can be the same."
He said the European Union had already mapped out a clear plan to respond to Russia's involvement in the Ukraine conflict, and that plan included trade sanctions.
"So far I think we have been true to those steps that when Russia does something to destabilise Ukraine, a further step has been taken," he said.
"I hope that isn't necessary. I hope that even at this late stage President Putin takes a different path.
"He knows that if he were to continue down the destabilisation path further measures, like those that have already been introduced, will be introduced by America and the European Union."
