Her lawyers said in a letter quoted by the Daily Dispatch newspaper that since the house in Qunu was bought while the two were still married, traditional custom dictated it should be inherited by Madikizela-Mandela and their children.
"This position becomes applicable irrespective of whether the wife was divorced or not," lawyer Mvuyo Notyesi wrote in the letter dated July 18 -- the late leader's birthday, which is celebrated internationally as Mandela Day.
"In fact, the property in question was obtained by Mrs Madikizela-Mandela whilst the husband was in prison."
He divorced Madikizela-Mandela in 1996 and she was not named in his will.
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"The view we hold is that the... Property belongs to the generation of Mr Nelson Mandela and Mrs Winnie Madikizela-Mandela as their common and parental home," said Notyesi.
The legal firm could not be reached for comment.
Mandela's USD 4.3-million estate was released in February, two months after his death, and left his assets to various family members, personal staff, schools and the ruling African National Congress.
Mandela married Machel, the widow of Mozambique president Samora Machel, in 1998.
In the will, Mandela left his property in Qunu to the family trust "for the benefit of the Mandela family and my third wife and her two children".
"The Qunu property should be used by my family in perpetuity in order to preserve the unity of the Mandela family," the revered anti-apartheid hero and Nobel peace laureate stated in the will.
The Nelson Mandela Foundation said it had "no archival information" on when the property was bought.
In his autobiography, Mandela said that after his 1990 release from prison, "I set about plans to build a country house for myself in Qunu."
The floor plan of the house, which was completed in 1993, was based on the warder's house he lived in at Victor Vester prison near the southwestern town of Paarl, where he spent the last 14 years of his imprisonment.