Factionalism and patronage have diminished the ability of the ANC to lead the process of transformation and fulfil its mandate to the people, party president Cyril Ramaphosa said on Saturday.
He was delivering the party's election manifesto at the Moses Mabhida Stadium in Durban.
"As the ANC, we admit our shortcomings, we accept the criticism of the people and we are hard at work to correct our mistakes," he said to thousands of ANC supporters who filled up the stadium.
He said the last 25 years have demonstrated the "enormity and complexity" of the task of redressing the injustices of the past and advancing fundamental change.
"However, the last 25 years have also shown the great power of a nation working as one to achieve a common goal. The last 25 years have shown the South African people to be resourceful, resilient and determined," he said.
Ramaphosa also acknowledged that state capture and corruption have "weakened" some public institutions, "undermined effective governance and contributed to the poor performance of our country".
He said his party was in Durban on Saturday to present a plan that the party had "forged together" to respond to the challenges of the present unemployment, poverty and inequality.
"The 2019 elections provide an opportunity to restore our democratic institutions and to return our country to a path of transformation, growth and development," he said.
As he continued to deliver his address, scores of people were seen walking out of the stadium leaving hundreds of seats empty.