South Africa has asked the Constitutional Court to stop the proposed US auction of 29 items associated with Nelson Mandela, arguing they are protected heritage objects.

South Africa's government turned to the top court Tuesday in a bid to halt the auction in the United States of objects belonging to Nelson Mandela, arguing they are part of the country's heritage.

The four-year legal battle involves 29 items -- ranging from the anti-apartheid leader's identity card to some of his iconic shirts -- listed for sale by a US auction house working with one of Mandela's daughters.

The government's heritage protection agency (SAHRA) and culture ministry asked the constitutional court to rule that the sale and export of the memorabilia would be illegal as they belonged in South Africa.

They argued the objects "are deemed to be heritage objects and their unpermitted export was unlawful", the court said in a summary.