Zuma suffers credibility crisis over finance ministers flip-flop

* Zuma flip-flop seen as a sign he has lost control

* #ZumaMustStillFall hashtag trending on Twitter

* Opinion divided over whether he could be ousted over blunder

* Markets recover after Gordhan appointed finmin

By James Macharia

JOHANNESBURG, Dec 14 (Reuters) - A blunder by Jacob Zuma that gave South Africa three finance ministers in five days has put the president's credibility on the line, with some senior ruling party figures, the opposition and ordinary people calling for his head.

Zuma's flip-flop was seen as a sign that he has lost control after he named the respected Pravin Gordhan as finance minister late on Sunday, in a stunning U-turn after the sacking last Wednesday of Nhlanhla Nene, who was replaced by David van Rooyen, a relatively unknown lawmaker.

Social media was abuzz with calls for Zuma to quit, with the #ZumaMustStillFall hashtag trending on Twitter, replacing #ZumaMustFall, and casting doubt on the political future of 73 year-old president at the helm of the ruling African National Congress (ANC).

Opinion is however divided over whether Zuma could be forced to relinquish the reins in Africa's most industrialised country. Some analysts expressed doubt that he would be ejected.

Zuma's fiasco has come at a time when the ANC is at a crucial stage with local elections looming next year, in which the party will face stiff competition from the opposition Democratic Alliance and the leftist Economic Freedom Fighters in urban areas, including the economic hub of Johannesburg.

Some key supporters of the ANC, Nelson Mandela's erstwhile liberation movement that has ruled since the end of apartheid in 1994, have called on Zuma to consider leaving office.

"Zuma must think about his position very seriously," said a former senior ANC legislator and respected anti-apartheid activist Ben Turok. "It may not be his death knell, but it's certainly the turning of the tide."

ZUMA CRISIS

Zuma's predecessor, Thabo Mbeki, was ousted by the ANC in 2008 in what was then the most dramatic political crisis since the end of white minority rule. The party recalled Mbeki before his term ended, and he agreed to step down.

The precedent could be dangerous for Zuma if he fails to fulfil the hopes of his allies on the left.

"Zuma must recalled. Damaging the image of the country on regular basis. Mampara (fool) of the year! He should fall now!," said Michael Kwanele in a tweet.

But some analysts doubt that it will come to that.

Zuma, whose colourful private life has often overshadowed his status as the leader of Africa's most advanced economy, has survived several political and personal scandals, including accusations by the opposition that he spent $23 million in state-funded security upgrades to his rural home. Zuma denies any wrongdoing.