Tutu, who died on Sunday aged 90, had largely faded from public life in recent years but was remembered for his easy humour and characteristic smile -- and above all his fight against injustices of all colours.

His funeral will be held on January 1 at Cape Town's St. George's Cathedral, his former parish, his foundation said in a statement.

South Africa's President Cyril Ramaphosa called him a man of "extraordinary intellect, integrity and invincibility against the forces of apartheid".

Ramaphosa said Tutu's death was "another chapter of bereavement in our nation's farewell to a generation of outstanding South Africans who have bequeathed us a liberated South Africa," after the country's last apartheid-era president FW de Klerk died in November.

Former US president Barack Obama, the country's first Black leader, hailed Tutu as a "moral compass".

"A universal spirit, Archbishop Tutu was grounded in the struggle for liberation and justice in his own country, but also concerned with injustice everywhere," Obama said in a statement.

Mourners gathered at St. George's Cathedral, while others massed at his home, some holding flower bouquets, according to an AFP journalist.

South Africa's cricket team wore black armbands in Tutu's honour on day one of the first Test against India in South Africa.

Kenyan President Uhuru Kenyatta said Tutu had "inspired a generation of African leaders who embraced his non-violent approaches in the liberation struggle".

European leaders joined the chorus, with UK Prime Minister Boris Johnson calling him a "critical figure" in the struggle to create a new South Africa and French President Emmanuel Macron saying Tutu had "dedicated his life to human rights and equality".

Britain's Queen Elizabeth II said Tutu's death "deeply saddened" her, while the Vatican said Pope Francis offered "heartfelt condolences to his family and loved ones".

A tireless activist, Tutu won the Nobel Peace Prize in 1984 for combatting white-minority rule in his country.

He coined the term "Rainbow Nation" to describe South Africa when Nelson Mandela became the country's first black president in 1994.

And he retired in 1996 to lead a harrowing journey into South Africa's brutal past as head of the Truth and Reconciliation Commission, which revealed the horrors of apartheid.

However, Tutu has also criticised the ruling African National Congress (ANC) -- the vanguard of the fight against white-minority rule.

He challenged Mandela over generous salaries for cabinet ministers and stridently criticised the corruption that mushroomed under ex-president Jacob Zuma.

Ordained at the age of 30 and appointed archbishop in 1986, he used his position to advocate for international sanctions against apartheid, and later to lobby for rights globally.

Tutu was diagnosed with prostate cancer in 1997 and repeatedly underwent treatment.

His public appearances became rarer. In one of his last this year, he emerged from hospital in a wheelchair to get a Covid vaccine, waving but not offering comment.

The archbishop had been in a weakened state for several months and died peacefully at 7:00 am (0500 GMT) on Sunday, according to several of his relatives interviewed by AFP.

The Nelson Mandela Foundation called Tutu "an extraordinary human being. A thinker. A leader. A shepherd."

"He was larger than life, and for so many in South Africa and around the world his life has been a blessing," it said in a statement.

Tutu was born in the small town of Klerksdorp, west of Johannesburg, on October 7, 1931, to a domestic worker and a school teacher.

He trained as a teacher before anger at the inferior education system set up for black children prompted him to become a priest.

He lived for a while in Britain, where he would needlessly ask for directions just to be called "Sir" by white policemen.

Tutu relentlessly challenged the status quo on issues like race, homosexuality and religious doctrine and gave his pioneering support for the assisted dying movement.

"I do not wish to be kept alive at all costs," he said in The Washington Post in 2016.