The African National Congress (ANC) has degenerated into a "mad house", said eThekwini ANC councillor Lungi Cele on Monday as she announced her defection to the Congress of the People (Cope).

"The movement that was once renowned for its high level of discipline has degenerated into a mad house as, day in day out, senior leaders of the ANC unashamedly and publicly tarnish the image of other comrades who do not subscribe to the populist ideology," said Cele, who had been a member of the ruling party for the past 19 years, at a media briefing in Durban where she announced her resignation.

"Since 2005 we have witnessed foreign behaviour in our movement...Greed and hunger for power have become the order of the day in the ANC," she said.

"If one occupies a public office and does not succumb to the (Jacob) Zuma personality cult, they are insulted and easily edged out, paving the way for those... dancing to the correct tune."

Cele said ANC members were "castigated" if they were not 100 percent Zuma.

"This is done with the purpose of dispensing patronage and those affirmed in this fashion are expected to return the favour by siphoning monies from the State coffers and divert[ing] them towards the Zuma course," she said.

Cele described the eThekwini municipality as being run in a "mafia style".

"This presents a serious danger to our democracy. Although this is known to the leadership, very little is done to curb it since it helps strengthen the Zuma camp," she continued.

"Internal democracy has collapsed in the ANC. For the past few years, I have been treated as a leper since I decided to back Comrade Thabo Mbeki to be elected ANC President for the third time. This despite the fact that I was exercising my democratic right as enshrined in the ANC Constitution," she revealed.

Cele believed these were signs that a dictatorship had taken over.

"You shall support one person and one person only. This is against the principles and foundations on which this movement was founded and flies in the face of democratic efforts of our forefathers like John Dube, Albert Luthuli and Oliver Tambo," she said.

"I therefore took a decision that I will not fold my arms when our democracy is severely under threat.... Today, I am heeding the call by patriots to join a movement that will best represent the aspirations of democracy-loving people."

She called on South Africans to vote with their minds and not their heart by voting for Cope.

Cele said Cope was the only party that could stop South Africa from becoming another African "success story gone wrong".

Cope spokesman Siyanda Mhlongo said they were happy with their new member.

A position had yet to be allocated to Cele.