South Africa's former 800-metre world champion Mbulaeni Mulaudzi has been killed in a car crash on his way to an athletics meeting in Johannesburg.

President Jacob Zuma said he was shocked and saddened.

"The nation has lost a true hero and one of our most talented athletes," he said. World athletics body the IAAF, the South African Olympic committee and South Africa's ruling ANC party also paid tribute to Mulaudzi, who retired last year after a 13-year career during which he became the world's top-ranked 800 metres athlete.