A law firm representing the Abbotts School in Johannesburg says the auction will be held Tuesday at Winnie Madikizela-Mandela's home in the Soweto township.
South African media say Madikizela-Mandela defaulted on a USD 2,150 payment to the school, where a relative was studying. A court ruled against her in 2011. Her lawyer declined to comment.
Madikizela-Mandela, whose former husband became president after 27 years in prison, was an anti-apartheid leader in her own right.