The party that ended apartheid is losing its appeal among black South Africans, many of whom have grown frustrated waiting for the "better life for all" promised when the African National Congress won the historic multiracial elections 18 years ago.

The disenchantment with the ANC has been building gradually over the years. But it has intensified in recent weeks amid the ongoing, and often violent, labour unrest that has spread across the nation since the police killed 34 strikers at a platinum mine in August. It was the deadliest police action so far in post-apartheid South Africa.

In newspaper columns, on radio talk shows, blogs and social media, the ANC is facing a public outcry, accused of corruption, being ineffective, wasteful and out of touch with South Africa's impoverished masses. Even prominent anti-apartheid figures are publicly disparaging the ANC leadership, calling its credibility into question. Meanwhile, other critics, including senior ANC leaders, claim the party is divided and facing a crisis of leadership, as President Jacob Zuma battles allegations of misuse of public funds to renovate his private residence.

"Now, the honeymoon is pretty much over," said Robert Schrire, a political analyst at the University of Cape Town. "What we are seeing is that the average black South African is no longer blindly loyal to the ANC, but feels angry and betrayed."

When Nelson Mandela was elected as South Africa's first black president in 1994, there was a burst of hope that a new era of equality was on the horizon. The ANC promised sweeping social change to redress the inequalities forged under apartheid, which oppressed non-whites through a system of racial separation enforced by harsh laws and police brutality to ensure the supremacy of white South Africans.

But for many black South Africans, the initial excitement has turned to disappointment, as they struggle with high unemployment and a lack of housing, education, clean water and other services.

No one is suggesting that the ANC will lose its dominance over South Africa's political landscape any time soon. Sikhulu Ndwandwe, 33, a social worker, and his family have been waiting for 16 years for a house, and they don't expect to get one soon. Their only source of electricity is an illegal hookup.

At the same time, Mr Ndwandwe knows there are few alternatives. Since 1994, the ANC has overwhelmingly won every election and now controls two-thirds of the seats in Parliament. But the anger and disillusionment, if they continue to grow, could trigger more protests and violence, potentially destabilising the continent's largest economy. Already, the number of violent protests this year, mostly over land, housing or services, has grown dramatically from previous years.

As many as 80,000 miners, or 16 per cent of the mining sector's workforce, are believed to be on strike, demanding better pay and benefits. Thousands more have already been fired. Meanwhile, thousands of truckers have also staged strikes, threatening supplies of fuel and food. South Africa's credit rating has been downgraded, mining stocks have plunged and the rand has weakened. Foreign investors are apprehensive.

In Khutsong, a black township surrounded by gold mines 56 miles west of Johannesburg, many residents live in shack settlements, where electricity is illegally procured and water hauled from outside taps shared by many families. Public toilets are so filthy that some residents prefer buckets or holes.

Bafana Mashata grew up worshipping the ANC's leaders. In school, he learned how Mr Mandela, Oliver Tambo and other anti-apartheid stalwarts ended white rule. But he deplores the ANC leaders who now run his nation. "Mandela and our other heroes fought for our freedom," said Mr Mashata, standing outside his uncle's tin shack, which has no electricity or running water. "But our leaders now sitting on top of the chair don't care about us, only about themselves."

There has been progress. The black middle class, fuelled by affirmative-action policies, has grown in this nation of more than 50 million. In a report released in September, the South African Institute of Race Relations found that those with access to electricity reached 11.9 million in 2010, up from 5.2 million in 1996. Over the same period, the number of families with proper housing nearly doubled to 11 million and those with access to piped water increased to 12.7 million from 7.2 million.

Still, government figures show that about a quarter of South Africans lack proper housing, nearly a quarter have no electricity and nearly a fifth no proper sanitation. The government, its critics say, has a pitiful record in providing education, leading to shortages of skills; now, a quarter of the population is unemployed, up from 20 per cent in 1994.

Meanwhile, the gap between rich and poor has widened, creating one of the world's most unequal societies, says the World Bank. Today, whites still largely control South Africa's economy, and earn six times more than blacks, according to census data released last week.

The anger in the streets started mounting long before the miners' strikes. In the first seven months of the year, residents of black townships staged dozens of demonstrations, according to Municipal IQ, an independent research group that focuses on local government. There have been more protests than in any year since 2004, when the group started its monitoring.

"The fact is that there is a deep and growing mistrust of leaders in our country, and the expanding underclass feels it has no voice through legitimate formal structures," Jay Naidoo, a former general secretary of the Congress of South African Trade Unions and senior ANC leader, wrote on his blog. "Violence becomes the only viable language." South Africa's leaders, he added, are failing those who sacrificed their lives to end apartheid.

When President Zuma was elected in 2009, many thought his populist zeal would translate into more help for South Africa's poor. But he quickly became entangled in scandal after scandal. Today, he is facing an official investigation and public rage over plans to upgrade his private homestead in Nkandla, in KwaZulu-Natal province, at a cost of $27m to taxpayers. The renovations reportedly include a helipad, underground parking, playgrounds, and even a medical clinic.

According to local news reports, the cost dwarfs the amounts spent on the residences of previous presidents Mandela, Thabo Mbeki and FW de Klerk. But Mr Zuma's aides insist he is personally paying for many of the upgrades.

Nevertheless, "Nkandlagate", as it is has been dubbed, has further eroded the credibility of the President and the ANC, say critics. Now, Mr Zuma, 70, is facing a battle for re-election as ANC president in December. Other ANC leaders are also viewed as out of touch, with some criticised for having ties to mining companies, driving luxury cars and using their political influence to become extremely wealthy.

The party's problems have provided an opening for Julius Malema, a controversial former ANC youth leader. Publicly attacking Mr Zuma, he has seized on the outrage over the miners' killings to rebuild his popularity since his expulsion from the ANC this year for hate speech, including calls to kill whites.

Some anti-apartheid stalwarts say the ANC has yet to make the transition from leading freedom fighters to leading a democratic nation. "I think we need to find a way of rediscovering the dreams that drove all of us to sacrifice so much," said Mamphela Ramphele, a prominent anti-apartheid activist and the partner of Steve Biko, the black consciousness leader killed in police custody in 1977. Biko, she said, "would be disappointed" at today's South Africa.