South Africa's government has opposed a legal bid by Winnie Madikizela-Mandela to claim ownership of her ex-husband Nelson Mandela's rural home, in an ongoing dispute over his estate.

In court papers, Mrs Madikizela-Mandela said that South Africa's first black president had unlawfully registered the property in his name, reports say.

Mr Mandela died nearly a year ago, and left his ex-wife out of his will.

His estate was provisionally valued at 46 million rand ($4.3m; £2.5m).

The thrice-married Mr Mandela divorced Mrs Madikizela-Mandela in 1996.

The two were South Africa's most celebrated political couple until their marriage collapsed after 38 years.

'Land fraud'

Mrs Madikizela-Mandela launched court action in October, saying she had "customary rights" to the rural home they once shared in Qunu village.

She says Mr Mandela may have committed land fraud when he registered the property in his name, the South African Press Association (Sapa) reports.

In papers filed in the Mthatha High Court last month, she said the ex-president had incorrectly used part of the State Land Disposal Act by donating the land to himself, according to the local Dispatch newspaper.

'Large family'

Her lawyers want Mr Zuma and the Department of Rural Development to produce official records proving the property belonged to Mr Mandela, including the validity of the title deed, local media reports say.

She wants the registration of the property under Mr Mandela's name to be annulled by the court, the Dispatch reports.

In response, Mr Zuma's spokesman Mac Maharaj said that the state attorney had filed a legal notice to oppose the action, pending instructions from the president.

Mrs Madikizela-Mandela's lawyer Mvuzo Notyesi told the Dispatch that he was confident of their case.

"That is a completely irregular notice. We are told there is a notice. They cannot file a notice to oppose before they furnish us with the required information. It is completely premature and totally irrelevant," Mr Notyesi is quoted as saying.

In his will, the ex-president said: "The Qunu property should be used by my family in perpetuity in order to preserve the unity of the Mandela family."

Mrs Madikizela-Mandela believes the property is rightfully hers and says that it was given to her by abaThembu King Buyelekhaya Dalindyebo while Mr Mandela was in prison for his role in fighting white minority rule.

Mr Mandela was released in 1990 after 27 years in jail and became South Africa's first democratically elected president in 1994.

His large family - which includes grandchildren and great grandchildren - was hit by legal disputes over his wealth and burial site as he battled a recurring lung infection in the months leading to his death at the age of 95.

He was married to Graca Machel, the wife of Mozambique's late President Samora Machel, at the time of his death.

Mr Mandela has one surviving child, Makaziwe, from his first marriage to the late Evelyn Mase and two daughters, Zinzi and Zenani, from his marriage to Mrs Madikizela-Mandela.