South Africa's ruling African National Congress (ANC) party deputy leader Kgalema Motlanthe will be the party's candidate to replace President Thabo Mbeki until elections next year, the ANC confirmed Tuesday.

"It has been confirmed that Kgalema (Motlanthe) is the candidate for president," party spokesman Ishmael Mnisi said.

On Thursday, the ANC-dominated National Assembly is expected to vote in Motlanthe as acting president, formally ending Mbeki's nine-year stint as head of state.

Motlanthe is expected to preside only until general elections, slated for April or May next year. After the polls, which the ANC is hands-down favourite to win, party leader Jacob Zuma is almost certain to become head of state.

The Motlanthe announcement followed the first resignation by a senior cabinet member in solidarity with Mbeki, who was forced out office by the ANC on the weekend on suspicion of interfering in a corruption case against Zuma.

A spokesman for Deputy President Phumzile Mlambo-Ngcuka confirmed Tuesday she had handed in her resignation to Mbeki.

While further cabinet resignations were expected, the wholesale bleed of ministers that had been feared after Mbeki agreed to resign Sunday, appears to have been averted.

Mlambo-Ngcuka had been unpopular with the Zuma faction in the ANC because she replaced Zuma when Mbeki sacked him as deputy president in 2005 on suspicion of corruption in a state arms deal. Little did Mbeki suspect then that he would later face a similar fate.

The bell tolled for Mbeki when a judge in the Pietermaritzburg High Court on September 12, in setting aside the corruption charges against Zuma on a technicality, inferred Mbeki had a hand in the decision to lay charges against him.

Mbeki's enemies in the ANC seized on the ruling to push for his resignation.

Mbeki has denied the allegations and approached the Constitutional Court, the country's top court, on Monday to seek leave to appeal on the grounds that the ruling was "prejudicial" to him and harmed his right to dignity.

Motlanthe, a former ANC secretary general and party moderate, was recently appointed as minister in the presidency to act as a bridge between the Mbeki government and the ANC.

A popular former union leader and anti-apartheid activist, who spent 10 years in prison on Robben Island, Motlanthe has often been tipped to take over from Zuma, in the event Zuma, who has been dogged by allegations of corruption, could not take office.