South Africa's Democratic Alliance (DA) on Sunday appointed John Steenhuisen as interim leader a month after the country's main opposition party was thrown into chaos by the sudden resignation of Mmusi Maimane.

Maimane, who was appointed as leader to broaden the traditionally white liberal party's appeal to black voters, quit in October in a blow to the DA's attempts to shed its image as a party of white privilege.

Race and class remain highly divisive issues in South Africa two decades after the end of apartheid, and some analysts think Maimane's departure could exacerbate an exodus of black voters from the DA, damaging its chances in 2021 municipal elections.

The DA's share of the vote fell to 20.8% in this year's election, from 22.2% five years ago, losing votes to the ultra-left Economic Freedom Fighters and the mainly Afrikaner Freedom Front Plus.

Steenhuisen's appointment until 2020 following a meeting of the DA's federal council, returns the party to white leadership after four years under Maimane, who said efforts to shake off perceptions that the DA was a party for the white minority had been undermined by some of his colleagues.

Others who quit warned it was lurching back to the right.

Steenhuisen told a press briefing that the race-based policies of the ruling African National Congress had not worked and that the DA was the only party fighting for a truly non-racial South Africa with equality of opportunity.

"Our fight is to lift more people out of poverty and lift them into opportunity, and restore the dignity of many South Africans who are still, 25 years after the end of apartheid, waiting for their freedom," Steenhuisen said.

Steenhuisen started his career as a party activist and rose through the DA's ranks from municipal councillor to national lawmaker, before becoming chief whip and now party leader.

While he embraces inclusive politics, analysts say his background means he is trusted by the party's old guard.

Ivan Meyer was also appointed during Sunday's meeting as the DA's interim federal chairperson, replacing Athol Trollip, who resigned alongside Maimane. Both he and Steenhuisen will hold the positions until permanent leaders are elected in 2020.