Author, activist and businesswoman Mamphela Ramphele launched a "party political platform" in Johannesburg on Monday.
"Today, I announce that I am working with a group of fellow citizens to form a party political platform that will focus on rekindling hope that building the country of our dreams is possible in our lifetime," she said at the old Women's Gaol in Braamfontein.
"We launch this initiative under the name Agang, or in the Nguni languages of our country, Akhani, which can be interpreted in English as 'Build South Africa'," she said in a speech.
The Limpopo-born Ramphele, who began her career as a qualified doctor and whose academic career has focused on studies of social conditions, said: "The country of our dreams has unfortunately faded for many of my fellow South Africans.
"...The dream has faded for the many living in poverty and destitution in our increasingly unequal society, and perhaps worst of all, my generation has to confess to the young people of our country: we have failed you," said Ramphele, who wore a black and white traditional outfit.
Describing herself as "no messiah", the former head of the World Bank, and member of the boards of several top companies, said the decision to enter party politics had not come easily.
Ramphele, who was once a partner of murdered Black Consciousness leader Steve Biko, said she had never been a member of a political party nor had she aspired to political office.
"I, however, feel called to lead the efforts of many South Africans who increasingly fear that we are missing too many opportunities to become that which we have the potential to become -- a great society."
She had travelled and listened to people and felt that: "The great society to which we committed ourselves following our relatively peaceful political transition is rapidly unravelling before our eyes."
The impressive achievements of the past 18 years were being "undermined by poor governance" at all levels of society.
"An unchecked culture of impunity and the abuse of power as well as public resources rob children, young people, rural and urban poor people of the fruits of freedom," said Ramphele.
"Corruption, nepotism and patronage have become the hallmarks of the conduct of many in public service.
"Corruption is theft. It steals textbooks from our school children. It steals drugs from sick people. It steals social grants from old people and poor children. It robs citizens of hope and destroys dreams," she said.
"This party political platform will declare war on corruption. It will work with all those in civil society as well as individual citizens and dedicated public servants who share our concerns to fight this scourge."
Speculation has been rife that Ramphele would form her own party. It was reported last year that she had turned down an invitation to join the Democratic Alliance.
Since last year she has resigned from her places on various boards, including those of the Anglo American Corporation and Gold Fields.