The royal family to which Nelson Mandela belonged has called on his family not to intimidate or undermine his widow Graca Machel.
It follows unconfirmed reports that some members of the Mandela family want Mrs Machel to leave the home she had shared with him in Johannesburg.
Mrs Machel should not be subjected to abusive language or threats, the AbaThembu royal family spokesman said.
Mr Mandela, South Africa’s first black president, died on 5 December.
He was buried on 15 December at his village, Qunu, in South Africa’s Eastern Cape province.
Mr Mandela was revered across the world for his role in fighting white minority rule, and promoting reconciliation after becoming president in 1994.
He spent 27 years in prison, before being released in 1990.
While Mr Mandela was seriously ill earlier this year, some of his children and grandchildren became embroiled in disputes for control of his legacy and estate.
On Sunday, South Africa’s City Press newspaper reported that Mrs Machel, 68, had endured rejection and abuse from her husband’s family for the past six months.
It said it had learned from six sources inside and outside the Mandela household that Mrs Machel had been told to leave the house in Johannesburg’s upmarket Houghton suburb as soon as Mr Mandela died.
In a statement on Tuesday, AbaThembu royal family spokesman Daludumo Mtirara said that Mrs Machel was currently in mourning and should be shown respect.
Mr Mandela’s death did not “terminate his commitment” to her, he added.
“Nkosikazi Nosizwe Graca Machel remains the umbrella of the Mandela family and members of the family who do not respect her must refrain from that trend because it is a disgrace that undermines our custom,” Mr Mtirara said.
“We do not doubt her contribution in the later years of the world icon,” he added.
Mr Mandela married Mrs Machel, the wife of Mozambique’s late President Samora Machel, on his 80th birthday on 18 July 1998.
He had been married twice before, to Winnie Madikizela-Mandela and the late Evelyn Mase.
He is survived by children and grandchildren from these two marriages.
After Mr Mandela’s death, Mrs Madikizela-Mandela dismissed as “mischievous” reports that the feud within the family had resumed.
She said Makaziwe, Mr Mandela’s eldest daughter from his marriage to Evelyn Mase, would be the head of the family.
However, Mr Mtirara said the royal family recognised Mr Mandela’s grandson Mandla as the most senior member of the family.
Makziwe and Mandla were involved in a bitter dispute over the reburial of some Mr Mandela’s relatives in June.
Mr Mandela was born into the AbaThembu royal family, and in 2007 endorsed the appointment of Mandla as a traditional chief.
Mrs Madikizela-Mandela was prominent at services to honour Mr Mandela, even though he divorced her in 1996, saying their relationship had broken down.