Prime Minister Anthony Albanese has paid tribute to late Soviet president Mikhail Gorbachev, saying the world had lost a giant of the 20th century.

Mr Gorbachev, who ended the Cold War without bloodshed but failed to prevent the collapse of the Soviet Union, has died at the age of 91, hospital officials in Moscow say.

Mr Gorbachev, the last Soviet president, forged arms reduction deals with the US and partnerships with Western powers to remove the Iron Curtain that had divided Europe since World War II and bring about the reunification of Germany.

“Mikhail Gorbachev passed away tonight after a serious and protracted disease,” Russia’s Central Clinical Hospital said early on Wednesday (Australian time).

Mr Albanese said Mr Gorbachev had changed the world for the better.

“He brought openness to a closed society with his policy of glasnost. With perestroika, he began to restructure a political and economic system deeply resistant to any such attempts,” he said on Wednesday.

“Mikhail Gorbachev was a man of warmth, hope, resolve and enormous courage, and in a world that was profoundly divided, he was driven by an instinct for cooperation and unity.

“Ultimately, he lifted a great shadow that lay across humanity.”

Russian President Vladimir Putin was cooler. Kremlin spokesman Dmitry Peskov told Interfax news agency that Mr Putin expressed “his deepest condolences” for Mr Gorbachev’s death.

“Tomorrow he will send a telegram of condolences to his family and friends,” he said.

Mr Putin said in 2018 he would reverse the collapse of the Soviet Union if he could, news agencies reported at the time.

In 2005, Mr Putin called the event the “greatest geopolitical catastrophe” of the 20th century.

World leaders pay tribute

US President Joe Biden said Mr Gorbachev was “a man of remarkable vision”

“He believed in glasnost and perestroika – openness and restructuring – not as mere slogans, but as the path forward for the people of the Soviet Union after so many years of isolation and deprivation,” he said.

“These were the acts of a rare leader – one with the imagination to see that a different future was possible and the courage to risk his entire career to achieve it. The result was a safer world and greater freedom for millions of people.”

The Reagan Foundation and Institute said it mourned the loss of Mr Gorbachev – “a man who once was a political adversary of Ronald Reagan’s who ended up becoming a friend”.

“Our thoughts and prayers go out to the Gorbachev family and the people of Russia,” it said.

British Prime Minister Boris Johnson, citing Mr Putin’s invasion of Ukraine, said Mr Gorbachev’s “tireless commitment to opening up Soviet society remains an example to us all”.

European Commission chief Ursula von der Leyen said Mr Gorbachev had opened the way for a free Europe.

Man who changed history

After decades of Cold War tension and confrontation, Mr Gorbachev brought the Soviet Union closer to the West than at any point since WWII.

But he saw that legacy wrecked in the final months of his life, as Mr Putin’s invasion of Ukraine brought Western sanctions crashing down on Moscow, and politicians in both Russia and the West began to speak openly of a new Cold War.

“Gorbachev died in a symbolic way when his life’s work, freedom, was effectively destroyed by Putin,” said Andrei Kolesnikov, senior fellow at the Carnegie Endowment for International Peace.

Mr Gorbachev won the Nobel Peace Prize in 1990.

He will be buried in Moscow’s Novodevichy Cemetery next to his wife Raisa, who died in 1999, said Tass news agency, citing the foundation that the former Soviet leader set up once he left office.

When pro-democracy protests swept across the Soviet bloc nations of communist Eastern Europe in 1989, Mr Gorbachev refrained from using force – unlike previous Kremlin leaders, who had sent tanks to crush uprisings in Hungary in 1956 and Czechoslovakia in 1968.

But the protests fuelled aspirations for autonomy in the 15 republics of the Soviet Union, which disintegrated over the next two years in chaotic fashion.

Mr Gorbachev struggled in vain to prevent that collapse.

“The era of Gorbachev is the era of perestroika, the era of hope, the era of our entry into a missile-free world … but there was one miscalculation: we did not know our country well,” said Vladimir Shevchenko, who headed Mr Gorbachev’s protocol office when he was Soviet leader.

“Our union fell apart, that was a tragedy and his tragedy,” RIA news agency cited him as saying.

On becoming general secretary of the Soviet Communist Party in 1985, aged just 54, he had set out to revitalise the system by introducing limited political and economic freedoms, but his reforms spun out of control.

His policy of “glasnost” – free speech – allowed previously unthinkable criticism of the party and the state, but also emboldened nationalists who began to press for independence in the Baltic republics of Latvia, Lithuania, Estonia and elsewhere.

Many Russians never forgave Mr Gorbachev for the turbulence that his reforms unleashed, considering the subsequent plunge in their living standards too high a price to pay for democracy.

“He gave us all freedom – but we don’t know what to do with it,” liberal economist Ruslan Grinberg told the armed forces news outlet Zvezda after visiting Mr Gorbachev in hospital on June 30.

“Gorbachev lived to see some of his worst fears realised and his brightest dreams drowned in blood and filth. But he will be remembered fondly by historians, and one day – I believe it – by Russians,” said Cold War historian Sergey Radchenko.

The division of opinion among Russians was highlighted in a 1998 TV advertisement for Pizza Hut, in which Mr Gorbachev appeared with his granddaughter, Anastasia Virganskaya.

Airing just a few months before the chain opened in Russia, it shows Mr Gorbachev and the little girl eating pizza when they are spotted by another family – who begin to argue about the former leader’s legacy for the country.

-with AAP