The replacement of South Africa's African National Congress by a new ruling party would just be democracy in practise, theologian Barney Pityana has said.

Pityana was a founder member of South Africa's Black Consciousness Movement along with the legendary Steve Biko in the 1970s and is now rector of the Anglican, College of the Transfiguration in Grahamstown.

"I am convinced that politicians and organisations don't change on the basis that it is nice to change. They do not change through moral speculations of interest," said Pityana speaking in Johannesburg.

"They change if they perceive a political threat to their standing. We are in a state where the ANC is recognising this moment that there is a political threat.

"That I think is good for South Africa and for democracy," Pityana said in a speech December 4 at a "State of Democracy debate" at the Constitutional Hill in Braamfontein, Johannesburg.

Separately Anglican Archbishop Emeritus Desmond Tutu urged South Africans on December 5, one year after Nelson Mandela's death, fellow to emulate the anti-apartheid hero's example.

"Our obligation to Madiba is to continue to build the society he envisaged, to follow his example," Mandela's fellow Nobel Peace Prize laureate Tutu said in a statement.

"A society founded on human rights, in which all can share in the rich bounty God bestowed on our country. In which all can live in dignity, together - a society of better tomorrows for all."

Mandela died on December 5 last year, after a long illness that forced him to spend much of 2013 in hospital.

The ANC, once led by Nelson Mandela, has ruled since the first all-race elections in 1994, but it is overseeing a faltering economy and opposition accusations it is undermining free speech and democracy.

Pityana, once a member of the ANC, noted that President Jacob Zuma had admitted at a recent ANC Youth League event that the party was in trouble, which was a positive development.

"He said the African National Congress was in trouble... The leader of the ANC recognises that the party is in trouble," the South African Press Association reported.

"The ruling party is in a panic and doesn't know how to handle a situation they haven't encountered before.

"It's not a problem of Parliament but of the ANC. I got a chill down my spine seeing the Speaker sitting there, pointing fingers [and shouting orders].

"Conduct begins with the Speaker. The current Speaker doesn't have the dignity of the house that she expects of others."