In an interview with Reuters, Democratic Alliance (DA) leader Zille said the unprecedented mining turmoil, including the police killing of 34 strikers at Lonmin's Marikana platinum mine in August, had exposed unsustainable contradictions in Nelson Mandela's 100-year-old ANC.
She attacked the veteran liberation movement that has ruled South Africa since the end of apartheid as "essentially a patronage-driven party", with those at the centre keeping power by controlling access to lucrative government contracts. It would be impossible for the ANC to keep organised labour and communists under the same roof as mega-wealthy post-apartheid industrialists such as Cyril Ramaphosa, a top ANC decision-maker and one of Lonmin's biggest shareholders.
"The next five, six, seven years, up to 2019, will see the ANC come apart. It can't encapsulate and hold together those divergent ideologies in one coherent political party," Zille said in the interview late on Friday.
She described the Marikana shootings, the bloodiest security incident since the end of white-minority rule in 1994, as a "catalytic event" that had exposed the frailties of the formal three-way alliance between the ANC, unions and Communist Party.
"It has never been so dramatically illustrated – big government, big business, big unions – and the ANC being the common denominator between all three."
ANC spokesperson were not immediately available for comment.
In the past, the party has dismissed reports of internal divisions as the product of a hostile media and over-excitable political analysts.
The ANC has enjoyed a 60%-plus majority at the ballot box in all four national elections since the end of apartheid. However, its share of the vote has been declining gradually. Zille's DA now controls the Western Cape province that includes Cape Town, and secured nearly one in four of the votes cast nationally in 2011 local elections.
The DA has its origins as the liberal, anti-apartheid party among whites in the era of white minority rule, but is determined to shake its reputation as a political haven for whites, who make up just 9% of the population. Two of the DA's most recent senior appointments – its leader in Parliament and its national spokesperson – are both black.
Zille, a white former journalist and anti-apartheid activist, said the DA's electoral success proves its multi-racial appeal. "You can't be a white party and get 24% of the vote," she said. "The sums don't add up."
South Africa's average age is 25, according to 2011 Census results released this week, meaning almost half its population are so-called 'Born Frees', with no memory of the institutionalised racism of apartheid.
By contrast, the ANC's non-racial credentials have been called into question in the last two years by incidents such as now-expelled youth leader Julius Malema popularising an anti-apartheid song that advocates the killing of white farmers.
"The ANC only has the race card left. That's all it has and it's becoming less and less believable," Zille said.
'Big man syndrome'
The ANC and President Jacob Zuma have been criticised for their handling of the mining crisis, which triggered ratings downgrades, hit economic growth and tarnished South Africa's investment image.
Investors have also become concerned about the spread of corruption and cronyism under Zuma, who came to power in 2009 only after the dropping of graft charges in circumstances that continue to cause controversy three years later.
Zille said the strength of South Africa's post-apartheid Constitution, its courts and institutions such as the media meant the country would pull through in the long term, and foreigners should not lose faith. "I'd certainly put my money into South Africa," she said.
But she also said the country suffered from "big man syndrome", the tendency for power to be concentrated in the hands of a single individual, which has bedevilled post-colonial Africa.
"We've got a very strong economic base, a very strong civil society and although we have a big man syndrome in politics – yes, we do – there are enough checks and balances and counterveiling forces to prevent it entrenching itself to destroy our democracy."
She also said there was no doubt about Zuma winning re-election as head of the ANC at a party congress in the central town of Mangaung in December, teeing him up for another four years in power as national president from 2014. "It's sewn up," she said. – Reuters