Having Russia at the G20 table after President Vladimir Putin has been accused of war crimes would be "a step too far," Scott Morrison says.
The prime minister says Australia shares the United States' assessment that war crimes have been committed in Ukraine.
"We know Vladimir Putin's form when it comes to taking the lives of innocent civilians. Russia has form," he said.
Mr Morrison said Australia had been raising concerns about Mr Putin's attendance at the G20 summit in Bali in November.
"The idea of sitting around a table with Vladimir Putin, who the United States are already in the position of calling out war crimes in Ukraine, for me is a step too far," he told reporters in Melbourne on Thursday.
He appeared to rule out an Australian boycott of the G20, saying it would be disappointing if serious issues the forum deals with weren't addressed.
"We want to make sure that the G20 for Indonesia is successful and we want to work closely with Indonesia as our partner," he said.
"We want it to focus particularly on the challenges of our region in the Indo- Pacific ... (but) we need to have people in the room that aren't invading other countries."
Foreign Minister Marise Payne said Australia was working with other G20 nations to determine whether Mr Putin should be allowed to attend this year's summit.
"These are very sensitive issues we are dealing on, not just in relation to the G20, but multiple international and multilateral organisations where this is a matter that we have to address that," she said.
"We work closely with other members of the G20, particularly Indonesia, on this."
Expelling Russia's ambassador to Australia also remains an option, one month on from the invasion of Ukraine, the foreign minister said.
Ahead of a major NATO summit in the wake of the invasion, Senator Payne said there was still a united front of other nations against Russia.
"There are a range of approaches globally, but the importance of the unity in that coalition ... is a very strong and unified coalition against Russia's illegal war," she told ABC Radio on Thursday.
"We never stopped seeking a diplomatic resolution ... and that is essential.
While Senator Payne said Australia had engaged with Russia's ambassador and its diplomats since the invasion began last month, the government was still considering whether to expel the ambassador.
"I'm not going to speculate on Australia's approach. I have said (expelling the ambassador) remains a live option on the table for this government," she said.
"At the same time, it is potentially useful to have direct lines of communication with, in this case, the Russian government ... we're working with partners we always do to determine the best approaches."
Senator Payne said the sanctions placed on Russia by western nations were a warning to other nations.
"It's a lesson to all authoritarian regimes ... that there is a cost for unilateral action such as this, in this case, the illegal invasion of a country like Ukraine," she said.
US President Joe Biden is heading to Europe to take part in the emergency NATO summit, along with a meeting of the G7 and European Council.
Mr Biden will also visit Poland, which has taken in more than 3.6 million Ukrainian refugees since the invasion began.
