Nelson Mandela, South Africa's first black president, turns 92 years old on Sunday, as the world celebrates the first international day in his honour.

Global leaders and ordinary people in South Africa and abroad have committed to devoting 67 minutes of their time to community service, to mark the number of years Mandela spent in politics.

His birthday was in 2009 recognised by the United Nations as "Nelson Mandela International Day" and will be celebrated across the world.

The increasingly frail leader is spending the day with family at his Johannesburg home.

Local politicians united in wishing the anti-apartheid icon well on his birthday, with international leaders hailing his contribution to global politics and the fight for human rights.

"President Mandela has given 67 years of his life, now what we all could do is try to use 67 minutes of our lives, and change the world for the better," said Martti Ahtisaari, former president of Finland.

Ahtisaari is a member of The Elders, an independent group of eminent global leaders formed by Mandela in 2008.

Mandela was jailed for 27 years by the country's white minority government for resisting apartheid rule.

On his release in 1990, he led negotiations with apartheid rulers, a process that culminated in his election as the country's first black president in 1994.

United States Secretary of State Hillary Clinton described Mandela as a hero to people of all backgrounds.

"His story is filled with an amazing strength and integrity of spirit. There is no one more deserving of this unprecedented international recognition," said Clinton.

"I am delighted to offer him my warmest wishes on this special day," she added.

Mandela has made few public appearances since he retired from public life in 2004.

Spending day with family, friends and children
Last week he arrived at the World Cup closing ceremony to wave at adoring football fans before the final match kick-off. He did not stay for the game.

He had campaigned for the country to host the event, but the death of his great-grandchild on the eve of the tournament's opening forced him to cancel his planned appearance.

His family said a group of nearly 100 children from villages around his childhood home in the rural Eastern Cape would spend the day with him.

President Jacob Zuma will address thousands of villagers at Mandela's birthplace Mvezo, one of the poorest areas in the country.

Even in Mvezo, villagers have been urged to spent 67 minutes of their time helping each other.

"Madiba's 67 years of uninterrupted and selfless service to the people of South Africa and the world culminated in the birth of a new South Africa, united in diversity," said Zuma in a statement.

Mandela used to celebrate his birthday by throwing a feast for the village, with several cows being slaughtered.

He stepped down as president in 1999, after serving one term in office. He is still revered around the world for promoting peace and fighting against racism and HIV/Aids, through his 46664 campaign.

On February 11, South Africa celebrated the 20th anniversary of Mandela's release from prison -- a day credited with shaping the history of the country.

"Nelson Mandela has given us a wonderful opportunity and duty to do something positive and active on Mandela Day," said Jimmy Carter, former US president.

Scores head for Mvezo
Meanwhile, scores of people were flocking to the Mvezo royal palace on Sunday, Mandela's birthplace in the Eastern Cape, for birthday celebrations.

Some VIPs arrived in helicopters and expensive cars while ordinary people arrived on foot or horseback.

By 10am, the Mvezo multi-purpose centre was a hive of activity.

President Jacob Zuma -- who arrived in an army helicopter -- was scheduled to pay homage to Mvezo Royal Chief, Mandla Mandela, the grandson of the former president. - AFP, Sapa