Pretoria: South Africa's opposition Democratic Alliance led in three major cities on Thursday as votes were counted in local elections, threatening to deal the biggest electoral blow to the African National Congress since the end of apartheid two decades ago.

The ANC - which ended white-minority rule when it swept to power in the country's first democratic elections in 1994 - held a big lead in the national count.

But it was behind the opposition DA in the municipalities that include the cities of Pretoria, Johannesburg and Port Elizabeth, areas which it has held virtually unopposed since the end of apartheid.

A significant loss of support for the ruling party in these areas could reshape the political playing field ahead of the 2019 national election, and may also embolden President Jacob Zuma's rivals within the ANC to challenge him.

The vote comes against the backdrop of increasing anger among voters at high unemployment and a lack of basic services as Africa's most industrialised country teeters on the edge of a recession, as well as a string of corruption scandals surrounding Mr Zuma.

Many ANC supporters are switching allegiances to the DA, bolstering its attempts to attract black voters and shake off its image of a party that chiefly serves the interests of the minority white community.

With about half of the vote counted in the national count, the ANC held a 52 per cent lead, against 31 per cent for the DA and 9 per cent for the radical left-wing Economic Freedom Fighters. Final results are expected by Friday.

The DA, which last year elected its first black leader Mmusi Maimane, was leading the ANC in Tshwane municipality, home to the capital Pretoria, in Johannesburg and in Nelson Mandela Bay, the area named after the anti-apartheid hero who led the ANC to power and which includes the city of Port Elizabeth.

The DA is expected to maintain its control of Cape Town, the only big city currently not run by the ANC, where it had a large lead over the ruling party.

The DA said it was "buoyant" about the growth in support across the country.

"It looks like we are going to be in government in a whole lot of places where we weren't in government before," said James Selfe, a senior DA executive.

The Economic Freedom Fighters (EFF), which is led by firebrand Julius Malema, Zuma's one-time protege and former ANC youth leader, is participating in only its second election and was running a distant third in the national count.

It is, however, winning some support from voters frustrated about inequality in a country where black people make up 80 per cent of the 54 million population, yet most of the economy in terms of ownership of land and companies remains in the hands of white people, who account for about 8 per cent of the population.

Many South Africans who queued up to vote across the country said they were worried about Mr Zuma's performance and the state of the economy, where one in four in the labour force is unemployed.

Mr Zuma survived an impeachment vote in April after the Constitutional Court said he breached the law by ignoring an order to repay some of the $16 million in state funds spent on renovating his private home.

In December, he rattled investors after changing his finance minister twice in a week, sending the rand plummeting. The currency has since recovered.

Mr Zuma has said he would repay some of the funds spent on his home and rejected criticism of his conduct.

Reuters