Mandela's relative hails conservationists

EDS: Not for use before 1830 (AEDT) on Wednesday, November 12.

SYDNEY, Nov 12 AAP - One of Nelson Mandela's great-grandsons has hailed conservationists gathered for a global conference in Sydney for their "selfless passion".

More than 4000 delegates are converging on the city for IUCN World Parks Congress 2014 this week, with Luvuyo Hlanganani Mandela a guest speaker at the opening ceremony at Sydney's Olympic Park on Wednesday night.

Mr Mandela, a social entrepreneur and youth advocate, said South Africa's first black president - who died last December aged 95 - shared their values.

"The seeds you plant today will grow into the shade that protects future generations from what would have been a much harsher reality," he told the audience.

"I know, in fact I am confident that your efforts today will secure a better future for our unborn sons and daughters.

"I stand here as living proof of one man's tireless efforts and success in building a better reality for South Africa, and I would be so bold as to say, the world."

The opening event featured an Aboriginal smoking ceremony along with dance and music performances.

The theme for the conference, held every 10 years, is "Parks, people, planet: inspiring solutions".