By Steven Deare in Sydney

Australian political leaders have labelled Alexei Navalny a “courageous force for democracy” and made clear who they hold responsible for the Russian opposition leader’s reported death. 

Prime Minister Anthony Albanese on Saturday shared his sadness after Russian authorities claimed Mr Navalny died at the Polar Wolf Arctic penal colony where he was serving a three-decade sentence.

“Australian mourns the tragic death of Alexei Navalny, a courageous force for democracy in Russia,” Mr Albanese wrote on social media.

“His treatment was unforgivable, and our thoughts are with his family and with the people of Russia.”

The anti-Kremlin critic fell unconscious and died after a walk at the colony, Russian authorities claim.

The 47-year-old former lawyer was President Vladimir Putin’s most formidable domestic opponent. He overcame a poisoning attempt, questionable convictions, police beatings and other foul play.

Navalny earned admiration from Russia’s opposition for voluntarily returning to Russia in 2021 from Germany, where he had been treated for what Western laboratory tests showed was an attempt to poison him with a nerve agent.

Foreign Affairs Minister Penny Wong praised the dissident’s resilience and pointed the finger of blame.

“(Navalny’s) heroic opposition to Putin’s repressive and unjust regime inspired the world,” she said on X.

“We hold the Russian government solely responsible for his treatment and death in prison.”

Opposition leader Peter Dutton called Navalny a hero and urged world leaders to condemn Russian authorities for the death.

“There should be global condemnation, and I’m sure there will be,” he told reporters.

“There’s no question that people are losing their lives – men, women and children – in Ukraine this very moment because of the decisions taken by President Putin.

“He’s a murderous dictator and he’s certainly got blood on his hands in relation to Mr Navalny.”

Navalny’s wife Yulia Navalnaya said she was unsure if she could believe Russian officials.

Supporters hoped Navalny would eventually walk free to become a future Russian president, though many opposition activists expressed fear he was in grave danger in the country’s prison system.

His death, if confirmed, robs the Russian opposition of its most courageous leader in the months before an election.

Mr Putin is set to win what many consider will be a sham election, to maintain power until at least 2030.

–with Reuters