CAPE TOWN -- Former South African president Nelson Mandela, who turned 84 on July 18, celebrated his birthday with hundreds of mentally disabled children on Saturday.

His birthday party was held at a sports stadium in Polokwane, in the far north of the country, after a two-day special Olympics for the children who jostled in their excitement to greet him in "Happy Birthday Madiba" T-shirts.

According to an AFP report, Mandela called for greater acceptance for people with disabilities, saying like the country's millions of HIV/AIDS sufferers they should suffer no prejudice.

"It is important to treat children with disabilities of whatever nature as ordinary children, just as we should do with people with HIV/AIDS," he said.

"It is common practice today to hide and lock these children away, fearing rejection and resentment from our fellow community members. We need a more accepting, supportive and caring society to remove the shame, stigma and fear of those who find themselves with mental disabilities in their families."

The children sang both happy birthday and the national anthem for Mandela. He then gently scolded them for leaving out the Afrikaans and English parts of the anthem that date from the apartheid era, and asked for it to be repeated.

They complied, and then presented him with a huge birthday card and a cake with candles.

Mandela, who has recently started walking with a cane, spent his birthday at a friend's country estate outside London with his wife Graca Machel and her family and returned to South Africa on Saturday.

He said the Nelson Mandela Children's Fund would in future collaborate on projects with the special Olympics.