South African elder statesman and Nobel laureate Desmond Tutu has said he would no longer vote for the ruling ANC.
"I would very sadly not be able to vote for them after the way things have gone," he wrote in South Africa's Mail and Guardian newspaper.
Inequality, violence and corruption are among the reasons costing the ANC his support, he added.
Archbishop Tutu, 81, was a strong supporter of the ANC's struggle against white minority rule.
Former African National Congress leader Nelson Mandela became the country's first black leader after all-race elections in 1994.
"The ANC was very good at leading us in the struggle to be free from oppression," Archbishop Tutu wrote.
"But it doesn't seem to me now that a freedom-fighting unit can easily make the transition to becoming a political party," he continued.
Describing South Africa as "the most unequal society in the world", he highlighted corruption, unaccountability and weaknesses in the constitution as key issues that need to be addressed.
Archbishop Tutu was also strongly critical of past decisions made by the ANC government at the UN, particularly on Zimbabwe.
"The things we have voted for or against have been a disgrace. It has been a total betrayal of our whole tradition."
Archbishop Tutu campaigned against white minority rule and was awarded the 1984 Nobel Peace Prize.
But he has been increasingly critical of the ruling party in recent years.
In 2011, he accused the ANC government of "kowtowing" to China, after the government delayed issuing a visa for the Dalai Lama, who had been invited to attend the archbishop's 80th birthday celebrations.
In the opinion piece, he also warned South Africa to prepare for Mr Mandela's death.
"My concern is that we are not preparing ourselves, as a nation, for the time when the inevitable happens."
"He's 94, he's had a rough time, and God has been very, very good in sparing him for us these many years. But the trauma of his passing is going to be very much intensified if we do not begin to prepare ourselves for the fact that this is going to happen at some time," he added.
Although officially retired, Archbishop Tutu continues to speak publicly about the world's injustices and domestic politics.
He was recently discharged from hospital following an infection.