Zuma, who has himself been at the centre of several major corruption scandals, called on the African National Congress (ANC) to reform and turn around its fortunes ahead of elections in 2019.
South African President Jacob Zuma admitted on Friday that the ruling ANC party is beset by corruption and divisions that could threaten its uninterrupted hold on power since the end of apartheid rule.
Zuma, who has himself been at the centre of several major corruption scandals, called on the African National Congress (ANC) to reform and turn its fortunes around ahead of elections in 2019.
He was speaking at the party's fifth National Policy Conference at the Nasrec Conference Centre near Soweto, south of Johannesburg.
Zuma may stay on as national president until the election, but he is due to step down as ANC chief in December and the party faces a bitter internal leadership battle.
He said that the ANC needed to "cleanse itself" of "corruption, social distance, factionalism (and) abuse of power."
"Factionalism is a cancer that must be rooted out of the ANC," he said, opening a six-day policy meeting in Soweto, south of Johannesburg.
Corruption under Zuma
Critics accuse Zuma, 75, of allowing corruption to flourish since he came to power in 2009, and of being in the sway of the Gupta business family, allegedly granting them lucrative government contracts.
The president has been admonished by the country's highest court, and is fighting a judicial order that could reinstate almost 800 corruption charges against him over an arms deal in the 1990s.
"Access to state power and resources has led to perceptions and allegations that the ANC is a corrupt organisation," Zuma said, vowing to fight against graft.
His speech was greeted with only weak applause, though before the event his supporters at the venue sang songs praising him.
Zuma is seen as favouring his ex-wife, former African Union chief Nkosazana Dlamini-Zuma, to succeed him – rather than deputy president Cyril Ramaphosa.
Dlamini-Zuma sat directly behind the president, in full view of the television cameras, while Ramaphosa was loudly cheered when he arrived on the stage.
The clash between the two camps could provoke further political instability in South Africa, which this month slipped into recession and is also suffering record unemployment.
Ramaphosa, a wealthy former businessman and trade union leader, has remained largely loyal to Zuma but sharply criticised him after the sacking of the respected finance minister Pravin Gordhan in March.
Zuma took a swipe at his critics, saying that "some members and leaders of the ANC have become primary conveyors of negative information about their own movement."
The president admitted that economic growth was lower than expected and that local elections last year had been a "serious setback" for the ANC, when it lost about eight percent of its previous national support.
He blamed the fall in support on perceptions that "we are soft on corruption, we are self-serving and that the ANC is arrogant."
Some veterans of the struggle against apartheid rule, which ended in 1994, boycotted the conference, which ends on Wednesday.
The opposition Democratic Alliance party made gains in the local elections and hopes to benefit from the ANC's woes in the 2019 vote.