As Nelson Mandela turns 91 today, his family and his charitable foundation are trying to harness his iconic status around the globe to promote community service on his birthday.

Celebrities and politicians will also be holding concerts and other celebrations from Johannesburg to New York, where France's First Lady Carla Bruni-Sarkozy will join a glittering line-up led by Aretha Franklin and Stevie Wonder.

"We are humbled by the call for an annual Mandela Day in our honour. Our struggle for freedom and justice was a collective effort. Mandela Day is no different," South Africa's first black President said.

"It is our hope that people will dedicate their time and effort to improve the conditions within their own communities," said Mr Mandela in a videotaped message prepared ahead of his birthday.

"The focus is on community service, picking up the one element of Mr Mandela's legacy that should apply to us all, and that is service to mankind," said Ruth Rensburg of the Nelson Mandela Foundation.

Organisers are asking the public to dedicate 67 minutes to an act of service to others, a minute for every year since Mr Mandela took up the struggle for equality in South Africa.

Mr Mandela's eldest grandson and chief of the Mandela clan Mandla Zwelivelile Mandela told AFP he will spend the day in the Mvezo village where his grandfather was born, cleaning the graves of his great-great-grandparents.

The younger Mandela said his grandfather just two weeks ago came to the village to remind children of the collective struggle against white-minority apartheid rule.

He said: "There is no leader that exists alone. I existed with ordinary men and women of this country who sacrificed more than I ever did and they just chose me to be the face of this campaign'," said the grandson.

He said Mandela Day should "pay tribute to the collective effort of leadership" that helped bring democracy to South Africa and "to be able to plough back to communities where we came from."

Nelson Mandela spent 27 years in prison, emerging in 1990 committed to democracy and negotiating a deal that led to universal suffrage and the country's first black Presidency, earning him the Nobel Peace Prize in 1993.

Mr Mandela has officially retired from public life, but his name, image and presence are still sought after, with celebrities wanting to meet him and his ruling ANC seeking his continued endorsement.

Mandla Mandela, whose father's death of AIDS in 2005 prompted the former president to speak out against the stigma of the disease, is at the centre of a battle for the leader's legacy.

He denied reports that he sold the television rights to his grandfather's funeral to the public broadcaster SABC, while controversially arranging for his now-frail grandfather to appear at an election rally this year after a string of scandals in the ruling African National Congress.

Mandla said the rights to his grandfather's name and how it is used was of great concern to the family, warning Mandela Day itself risked "losing its purpose".

"Now people are already seeing this as a profit-making scheme and doing their own initiatives to reap rewards out of this."

Ms Rensburg of the Foundation says Mr Mandela's intellectual property is in safe hands and was monitored around the world, and stopped where necessary.

A London art gallery has come under fire for displaying prints of artwork that the exhibitors claim were signed by Mr Mandela. His lawyers say the signatures were faked.

"My serious concern is what becomes of the name after the old man has come and gone," said Ms Zwelivelile.

"We currently see that name commercialised, seeing my grandfather printed on coins and things. It is for us as a family to really become active participants as to what we desire for my grandfather's legacy to become."