South Africa's ex-president Jacob Zuma, who is facing corruption charges and served a short stint in jail, has said he is ready for a political comeback with the ruling party.

In a statement late Monday, Zuma, 80, said he has been asked by members of the African National Congress (ANC), which has ruled South Africa since the end of apartheid, to put himself forward as the party gears up to elect a new leadership.

"I will not refuse such a call should they deem it necessary for me to serve the organisation again," he said, adding he has been consulting with party leaders "in spite of the difficulties caused by my current legal situation".

The move comes amid heavy infighting within the ANC, ahead of a national elective conference in December.

The party is to hold internal polls to pick a new leader, who would then become the candidate for the next presidential election in 2024.

Current President Cyril Ramaphosa is hoping to secure a second term but faces a challenge from a faction loyal to Zuma -- a divisive figure whose name resonates with graft for most South Africans but remains a hero to many grassroots ANC members.

Zuma said he supports his ex-wife Nkosazana Dlamini-Zuma to replace Ramaphosa and hinted he would be prepared to serve as party chairman, another key role.

Support for the party of Nelson Mandela dropped below 50% for the first time in local elections last year, and the government is facing growing discontent over widespread poverty, unemployment, and a prolonged power crisis.

Zuma became president in 2009 but was forced to step down nine years later in favour of Ramaphosa, then vice-president.

In July last year he was jailed for 15 months for contempt of court after refusing to testify before a graft inquiry, but was released on medical parole just two months into the term.