Internal conflict and maladministration are among the reasons for Peter Marais' resignation from the Congress of the People, he said on Saturday.
Speaking by phone to Sapa, the former mayor of Cape Town confirmed he had left Cope.
"I have resigned from Cope. I have informed the party leadership," he said.
Marais described Cope as a "Mere mirage – a desert instead of an oasis".
"It is beset with internal conflict, cash strapped in the extreme and suffers from maladministration," he said.
Marais said his decision to leave had nothing to do with his position-number 40 – on the party's national elections list.
"This is not about how high or low I am on the list."
He also said he had not joined the African National Congress, although confirmed he had been invited to Luthuli house for discussions.
He declined to say what the subject of these discussions had been.
"I don't have a crystal ball. But as of today, I haven't joined the ANC," he said.
Sapa