Oct. 15 (Bloomberg) -- The split in South Africa's ruling African National Congress widened as former Gauteng provincial premier Mbhazima Shilowa quit the party and said he may join efforts to form a breakaway movement.

``I have taken this decision knowing fully well that I will be vilified, insulted and rebuked by people who a few days earlier regarded me as one of them,'' Shilowa told reporters today in Johannesburg.

Shilowa, a former general secretary of the Congress of South African Trade Unions, or Cosatu, is the third major figure to indicate he may join a rival party since Thabo Mbeki was ousted as president last month. Mbeki was replaced by deputy ANC president Kgalema Motlanthe after a High Court judge said his government may have pressured prosecutors to charge party president Jacob Zuma with corruption.

A splinter group led by senior anti-apartheid leaders may pose the most serious challenge to the ANC since it took power in 1994 and Nelson Mandela became South Africa's first black president.

Shilowa today described Mbeki's ouster as a ``putsch.''

The ANC suspended former party chairman and Mosiuoa Lekota on Oct. 13, after he said he was ``serving divorce papers'' on the ANC, as well as his former deputy, Mluleki George.

Shilowa's resignation was expected, ANC spokeswoman Jessie Duarte said in a phone interview today. ``We wish him well.''

`Elitist'

The Cosatu union federation said Shilowa's actions were motivated by personal ambition and showed he no longer cared about the poor.

``He changed from being a darling of workers to a member of expensive, elitist, whisky-drinking and cigar-smoking clubs,'' Cosatu said in an e-mailed statement. ``He presents himself as a democrat. In reality he is just a bad loser.''

As the former head of Gauteng, the richest of South Africa's nine provinces that includes the capital, Pretoria, and Johannesburg, the largest city, Shilowa could strengthen a rival party, Zwelethu Jolobe, a political science professor at the University of Cape Town, said today.

``Shilowa is a heavyweight,'' he said in a telephone interview. ``There is a very serious possibility that we could see the emergence of an alternative to the ANC.''

Fracture

The ANC began to fracture in 2005 when Mbeki dismissed Zuma as his vice president amid allegations of corruption. The divisions widened last December when Zuma wrested control of Africa's oldest political movement and won nomination as the ANC's presidential candidate in next year's elections.

Lekota, George and several other senior government officials resigned in protest after Mbeki resigned on Sept. 21. Lekota said on Oct. 8 that he would call a national convention to determine whether a rival party was viable.

Shilowa said he would serve as ``the convener and volunteer-in-chief'' of the meeting, which will take place on Nov. 2 at a venue that hasn't yet been chosen.

``We need to discuss in the convention how to foster democratic tolerance, even though we may disagree with such choices,'' Shilowa said. ``The convention needs to indicate on how we can focus on weeding out corrupt individuals wherever they may be found, regardless of social standing.''

The ANC won almost 70 percent of the 15.6 million votes cast in the last elections in 2004. Its closest rival, the Democratic Alliance, won 12 percent of the vote and has failed to win enough black supporters to crack the ANC's dominance.

Electoral Changes

Shilowa called for changes in the electoral process, including a direct election for president rather than the current system that allows the ruling party to appoint him.

Lekota and George, who were both jailed on Robben Island for anti-apartheid activities, were leaders in the United Democratic Front, formed in 1983 when the ANC was banned by the white-minority government.

Mbeki has yet to comment on the possible formation of a new party. Shilowa said he had not informed Mbeki of his decision to quit the ANC, and that the former president wasn't the driving force behind a new party.

To contact the reporter on this story: Mike Cohen in Cape Town at mcohen21@bloomberg.net

Last Updated: October 15, 2008 07:03 EDT