The Democratic Alliance (DA) will ask its voters to consider casting their votes for the Inkatha Freedom Party (IFP) in the Ward 99 by-election in Umkomaas to oust the African National Congress (ANC).

The move was announced at a joint press briefing at the Elangeni Hotel on Tuesday where both opposition parties cemented their intention to oust the ailing ANC in eThekwini.

"The DA's constituency head for Umkomaas Ward 99, Tim Brauseth, will be going out to explain to voters why we have done this, and why [it is] in their best interests to allow the IFP to contest, with consolidated opposition support behind them," said DA KwaZulu-Natal chairperson Dean Macpherson.

He added: "That is our message to them. If enough opposition voters get together and work together, we can get the ANC out."

IFP chief whip and treasurer Narend Singh said they wanted to send a strong signal to smaller parties that they could "alter the dynamics in eThekwini".

"South Africans know the ruling party has failed. Everywhere you look, there are failures. South Africans deserve better, and we can give you better as a collective of political parties."

There is a fragile coalition in eThekwini with the ANC, after its failure to secure a majority, relying on the Abantu Batho Congress (ABC), Singh said.

About 27 smaller parties backed the ANC.

"Many of them have a single seat. Our responsibility will be to start talking to each other and say, can we now come together and ensure the citizens of Durban get better."

Singh acknowledged that coalitions and agreements between political parties were often fragile, but said a win would "send a strong signal that we've arrived".

"When we say we have arrived, we mean everyone but the ruling party," he said.

Macpherson added that they wanted smaller parties to know that they were open to talks under the right circumstances.

"We are convinced that a united front in eThekwini can push the ANC out eventually. We hope that is a precursor to what can happen in the future."

"We want to stop the ANC from winning and return the city to its former glory. We all know how bad the condition of the city and country is under the ANC."

In late October, the DA and IFP conducted bilateral talks to bolster their relationship to pursue common interests.

One of the most pressing issue was to remove the corrupt ANC from power in eThekwini and KwaZulu-Natal.

eThekwini is experiencing a crisis with raw, untreated sewage spilling onto the streets and oceans in Durban.

The crisis comes after poorly maintained sewerage infrastructure was further damaged in floods that hit the area in April.

The City promised to avert the crisis by 1 December, but experts said that was unrealistic.

The city also has one of the of the highest numbers of rape cases, with other crimes also at all time highs.