JOHANNESBURG (Reuters) - South African President Cyril Ramaphosa will be badly weakened after presiding over the African National Congress (ANC) party's worst election result since the end of apartheid.

Results from around 71% of polling stations in Wednesday's election showed the ANC's vote share at less than 42%, a sharp drop from the 57.5% it secured at the last election in 2019 and well short of a majority for the first time in 30 years.

The electoral blow means the former liberation movement of Nelson Mandela will have to negotiate a coalition deal or other form of agreement with one or more smaller parties to govern the country. It may have to make policy concessions or cede prominent cabinet positions.

Former union leader-turned-businessman Ramaphosa will probably face calls to quit from opposition parties and critics in his deeply divided party, but a top ANC official has backed him to stay on and analysts say there is no obvious successor.

"There isn't a clear unifying candidate who could take over from Ramaphosa," said Anthony Butler, a politics professor at the University of Cape Town who wrote a biography of Ramaphosa.

A March opinion poll showed Ramaphosa had the highest approval rating among major politicians in this election, and factional battles in the ANC could complicate any attempt to mobilise against him.

Ramaphosa has not yet commented on the ANC's election performance. His spokesman said he would deliver remarks on Sunday when full provisional results are due to be announced.

TOUGH TEST

Ramaphosa's future as president has hung in the balance before, when a panel report found in 2022 that he may have committed misconduct over a stash of cash stuffed into furniture at his game farm.

He denied wrongdoing over that scandal, dubbed "Farmgate", and won a new five-year term as ANC leader later that year.

Wednesday's vote had been billed as the toughest test yet for the ANC because of voter anger over issues like high unemployment, crime and crippling power cuts.

Ramaphosa was elected ANC leader in late 2017 on a pledge to clean up the party's image and revitalise the economy after nine years of scandal, sleaze and economic decline under his predecessor, Jacob Zuma.

But an initial wave of euphoria when he became head of state in 2018 quickly faded.

More than six years on, the economy remains stagnant and scandals still swirl around top ANC officials.

The decisive blow in this week's vote was struck by his nemesis Zuma, who backed new party uMkhonto we Sizwe which outperformed expectations and made a big dent in ANC support, especially in Zuma's home province of KwaZulu-Natal (KZN).

"Jacob Zuma checkmated Ramaphosa and the ANC. He knew they were vulnerable in KZN," political analyst Ralph Mathekga said. "This is the end of Ramaphosa's project ... You can't lose elections and expect things to go on as normal."

INDECISIVE OR CONSENSUS BUILDER?

Ramaphosa has been criticised for appearing to prevaricate on crucial reforms to avoid exacerbating rifts in his party - a far cry from the decisiveness he showed as a union leader in the 1980s.

His supporters, however, applaud his consensus-building skills and his role in advancing South Africa's reputation as a champion of the so-called "Global South", shorthand for a group of low- and middle-income countries.

During the COVID-19 pandemic, Ramaphosa was one of the most prominent voices globally calling for fairer distribution of vaccines.

More recently South Africa filed a genocide case against Israel at the International Court of Justice, leading judges to rule this month that Israel must halt its military assault on the Gaza city of Rafah. Israel has vehemently rejected the allegations and pressed on with its offensive in Rafah.

On the campaign trail, Ramaphosa sought to play up the ANC's successes over the last 30 years, but critics say he has offered little in the way of new solutions to South Africa's biggest challenges.

At the ANC's final campaign rally before the election, he promised to "do better" before a crowd of tens of thousands of supporters gathered at a Soweto soccer stadium. Many filed out before he had finished his speech.

(Additional reporting by Nellie Peyton; Editing by Joe Bavier and Emelia Sithole-Matarise)

By Alexander Winning