The remains of three of Nelson Mandela's children were exhumed Wednesday to be returned to his childhood village following a bitter family feud over the ailing anti-apartheid hero's final resting place.

The public row comes as the 94-year-old former political prisoner, who became South Africa's first black president, lies critically ill in what is now his fourth week in hospital.

In dramatic scenes that unfolded in front of the world's media, a sheriff forced open the gates to the estate of Mandela's grandson Mandla with a pickaxe to allow three hearses to enter the property, where the disputed remains were moved in 2011, allegedly without the family's consent.

It came hours after a court in the nearby city of Mthatha ordered Mandla, 39, to immediately move the graves back to Qunu about 30 kilometres (20 miles) away, where Mandela grew up. Judge Lusindiso Pakade described the grandson's actions as "scandalous".

"The exhumation has been concluded now. The remains are being transported to the mortuary in Mthatha," said police spokesman Lieutenant Colonel Mzukisi Fatyela. "They will be kept there until the burial tomorrow (Thursday)."

Mandela has expressed his wish to be buried at his rural homestead at Qunu, and his daughters want to have the children's remains returned so they can be buried together.

More than a dozen relatives of the revered leader, including his wife Graca Machel, two of his daughters and several grandchildren, took Mandla to court over the dispute.

According to court documents submitted by the family on June 28 to support their case, Mandela is in a "perilous" condition on life support, local media reported.

"The anticipation of his impending death is based on real and substantial grounds. The applicants are desirous of burying their father and committing him to the earth in which his descendants' remains lie," according to court papers quoted by the Mail & Guardian and other media.

Political analysts said that rivalry over control of the Mandela legacy could be behind the court tussle.

"The legal battles underline broader divisions within the family," said Daniel Silke, director of the Political Futures Consultancy.

"They may well be related to financial gains and the exploitation of the Mandela name," he added, describing the squabbles as "distasteful".

The family is also seeking criminal charges of grave tampering against Mandla.

Previously the grandson has argued that Mandela should be buried at his birthplace Mvezo, where Mandla holds court as clan chief.

The disputed remains are of Mandela's eldest son Thembekile, who died in 1969, his nine-month-old infant Makaziwe, who died in 1948, and Mandla's own father Makgatho, who died in 2005.

The grandson's spokesman Freddy Pilusa insisted that Mandla was not opposed in principle to returning the remains to Qunu.

"He has never been against repatriation of those remains," Pilusa told AFP.

Mandela, who led the struggle against white-minority rule in South Africa, became president after the country's first multiracial elections in 1994, following 27 years in apartheid prisons.

He retired from public life in 2004. Rather than accept the hereditary title of chief of Mvezo himself, Mandela chose his grandson to take up the post in the Eastern Cape six years ago.

Mandla has since overseen changes including a new brick-paved road to the village.

A museum currently comprises a tiny outdoor display on Nelson Mandela.

But an impressive collection of tourism-oriented thatched buildings, including a cultural centre and accommodation, is currently under construction with state funding, alongside the offices of the traditional council and a conference centre.

South Africa's National Prosecuting Authority said Wednesday they would make a decision on whether to press grave tampering charges against Mandla after police have concluded their probe.