JOHANNESBURG (Reuters) - A racist Facebook post by a member of South Africa’s main opposition party has caused a national furor and left it scrambling to shake off its image of an organization that chiefly serves the interests of the minority white community.

Members of South African President Jacob Zuma's ruling African National Congress (ANC) political party march to the headquarters of the opposition Democratic Alliance (DA) during a march against racism in Cape Town, January 22, 2016. REUTERS/Mike Hutchings

The episode highlighted how racial tensions simmer in the country more than two decades after Nelson Mandela become its first black president, with wealth and income gaps that are still clearly visible along race lines fuelling perceptions of white privilege.

It could set back the Democratic Alliance’s efforts to attract black votes and present an effective opposition to the African National Congress (ANC), whose hold on power has been virtually untested since the end of apartheid despite rising discontent over an ailing economy and job losses.

The furor erupted this month after estate agent Penny Sparrow, a Democratic Alliance (DA) member, referred to black people as “monkeys” in a New Year’s Day rant on Facebook against littering at a public beach.

It triggered hundreds of posts on social media condemning the comments, in turn leading to nationwide media coverage and to some rival politicians saying Sparrow had expressed views secretly shared by many DA supporters - who, along with its political leaders, are predominantly white.

In the following days, the ANC organized several anti-racism marches attended by hundreds of people.

The DA was quick to denounce and expel Sparrow, but the episode dealt a blow to its drive to convince voters it is committed to an equal society, despite having elected its first black leader last year, Mmusi Maimane.

It risks costing the party the support of some black middle-class voters like Ndodana Nkomani, who had grown disenchanted with the ANC and was thinking of giving the opposition a chance at this year’s local government elections.

“Now I’m not so sure,” said the 27-year-old financial market analyst from Johannesburg. “It seems like apartheid is still alive and well.”

Mcebisi Ndletyana, a professor of political science at the University of Johannesburg, said the Sparrow post has exacerbated the DA’s credibility problem on the issue of race.

“Mmusi Maimane’s presidency started off on a good footing ... but they’ve taken a step back. Racial identity is a strong problem that the DA faces both at national and local elections and that problem has been compounded.”

Tensions in the country rose further when, days after Sparrow’s post, prominent Standard Bank economist Chris Hart suggested on Twitter that 25 years of ANC rule had perpetuated poverty and entrenched a tendency to blame whites for all of South Africa’s ills.

The tweet prompted mostly black youths to stage a protest march to the bank’s offices in downtown Johannesburg. Hart apologized for the comments, and said they were not meant to be racist, but he was suspended by the bank, whose CEO said racism and inequality were a drag on Africa’s most advanced economy.

JOBS, HOUSING

President Jacob Zuma’s ANC won 62 percent in 2014 parliamentary and presidential elections - similar to what the party garnered in the first democratic elections in 1994 - with the Democratic Alliance a distant second with 22 percent.

In the latest measure of the public mood, the ANC is expected to easily win local elections this year, even in the face of an economic downturn and public anger that it has not fully delivered on its promise to provide jobs, housing and quality education, among other services.

The DA also faces a growing challenge from the radical new Economic Freedom Fighters (EEF) which scored more than 6 percent in 2014 despite having been formed just months before the poll, winning support from black voters frustrated about inequality.

Black people make up 80 percent of the country’s roughly 54 million population, yet the lion’s share of the economy in terms of ownership of land and companies remains in the hands of white people, who account for around 8 percent of the population.

The DA is walking a difficult line, according to political analysts, to attract the black voters needed to win power while retaining its traditional support among white voters.

In a scathing newspaper column last week, former DA parliamentary leader Lindiwe Mazibuko, who quit to pursue studies at Harvard, urged the party to reflect “on a culture that isolates black members and leaders” and to “interrogate the almost exclusive dominance of white males”.

The party faced criticism from the ANC and EEF for briefly expelling, then reinstating its member of parliament Dianne Kohler Barnard after she shared a Facebook post last year praising former apartheid President PW Botha.

“It is not going to help the DA to try to be all things to all races,” Aubrey Matshiqi, a research fellow at the Helen Suzman Foundation, told Reuters.

“It’s not going to help to engage in double speak; using anti-racist rhetoric to attract black voters, and downplaying the question of race and the role of whiteness in racism in order to hold on to its traditional support base.”

DA leader Maimane urged racists not to vote for his party at a speech to supporters last week and his party has launched a nationwide campaign for its members to sign an anti-racism pledge.

But the latest furor over the online posts has undoubtedly benefited the ANC, analysts say, taking some heat off Zuma who is accused by his political opponents and analysts of mismanaging the economy, and boosting its bid to promote itself as the only party committed to a non-racial society.

“The ANC uses the race narrative and experiences to portray that the struggle is not finished, that the enemy has not quite been defeated,” said political analyst Susan Booysen of the University of Witwatersrand’s school of governance.