* ANC's 2014 election manifesto presented at mass rally
* Announces ban on officials doing business with the state
* President himself faces graft probe over home upgrade
* With Mandela gone, ANC faces tough election test
By Pascal Fletcher
NELSPRUIT, South Africa, Jan 11 (Reuters) - South African President Jacob Zuma announced a crackdown on corruption on Saturday, presenting his ruling ANC's manifesto for elections this year that will give the party its toughest political test since the end of apartheid.
Zuma, who has ruled Africa's biggest economy since 2009 and himself faces allegations of graft and abuse of power, announced the measures at a packed African National Congress (ANC) rally in the eastern province of Mpumalanga.
Two decades after South Africa's first multi-racial ballot won by Nelson Mandela, who died last month, the 102-year-old liberation movement is fighting to counter an erosion of voter support in presidential and legislative elections.
This threat comes from popular anger over persisting poverty and high unemployment in one of the most unequal societies in the world.
The ANC is still tipped to win the elections expected in April, when Zuma will stand for a second term as president.
However, criticism its leaders including Zuma are more interested in enriching themselves than in lifting up South Africa's struggling poor and jobless, have dented the party's self-projected role as the champion of the working class.
Zuma, who was booed in public last month at a memorial to Mandela, made a point of pledging the anti-corruption drive when he presented the ANC's 2014 elections manifesto to a partisan crowd in a soccer stadium in the city of Nelspruit.
"The ANC remains very clear that corruption must be fought wherever it occurs and in all its manifestations," Zuma said, winning cheers from supporters wearing the party's yellow, green and black colours.
Taking aim at a major source of corruption in South Africa - government tenders often awarded to political allies, friends and family members - Zuma said his administration would create a "central tender board" to allocate all government contracts.
Currently, government entities individually tender for services.
"We are changing the tender system in our country, which has caused a lot of problems," Zuma said, adding all public servants and representatives would be barred from doing business with the state, departing from the existing practice.
The president said any ANC and government officials found guilty of corruption by a court of law would be expected to step down from leadership positions.
Zuma, a polygamous Zulu traditionalist whose five-year rule has seen scandals, feeble economic growth and labour and social unrest, himself faces public outcry over a $21 million state-funded security upgrade to his private home.
He denies any wrongdoing.
CHALLENGE FROM THE LEFT
There were no big surprises in the economic strategy component of the ANC manifesto, with Zuma promising policies to back accelerated growth and long-term economic stability.
He did speak of "radical economic transformation" and increasing the state's role in the economy - for example, the state-owned mining company would be strengthened. But the ANC has already made clear nationalisation is not on the agenda.
Zuma said efforts would be made to improve housing and basic services. Poor delivery in these areas has resulted in almost daily protests by hard-up township dwellers.
He also promised the creation of 6 million jobs through an expanded public programme targeting young people, among whom the jobless rate is double the 25 percent national level.
Although Zuma listed advances over the last 20 years in tackling inequalities inherited from apartheid, the ANC faces a political challenge from the left, from disgruntled workers and some party defectors who propose more radical policies.
In December, South Africa's biggest union, the 330,000-member National Union of Metalworkers of South Africa (NUMSA), announced it would not support the ANC in the elections.
At Saturday's rally, leaders of the COSATU union federation and the South African Communist Party (SACP), which are the ANC's allies in government, appealed for unity.
"Workers must be careful that they are not separated from the ANC, because the only ones who will benefit will be the enemies of the revolution and their bosses," SACP Secretary-General Blade Nzimande told the crowd.
Among new formations that have emerged to confront the ANC in the elections is one led by a former supporter and now vocal critic of Zuma, ex-ANC Youth League leader Julius Malema who was expelled from the party in 2012 for indiscipline.
Tapping into simmering discontent in South Africa's mines and townships, Malema's Economic Freedom Fighters (EFF) are taking on the ANC with a radical populist message advocating nationalisations and seizures of white-owned land.
Speaking before the ANC manifesto launch, Malema on Thursday described Zuma's policies as "an old CD with a scratch" and promised "exciting elections". (Additional reporting by Xola Potelwa in Johannesburg; Editing by Sophie Hares)