The Economic Freedom Fighters (EFF), led by the populist Julius Malema, has vowed to prevent Zuma from speaking until he has answered questions about the $24 million (19 million euros) of taxpayers’ money spent on “security upgrades” at his private residence.

The same issue triggered chaotic scenes in the assembly in August, after riot police were deployed to stifle a revolt by a group of EFF lawmakers, who drowned out Zuma, yelling: “Pay back the money”.

The episode marked the most tumultuous parliamentary session since the dawn of democracy 20 years ago, after the end of the racist apartheid regime.

Zuma has not returned to the chamber since the uproar and EFF lawmakers — dressed in their trademark “workers solidarity” outfits of red overalls, gumboots, hardhats and maid’s uniforms — have vowed to pick up where they left off.

When moves were made to ban their outfits from parliament, the firebrand Malema threatened that they would turn up in the nude. The proposal was promptly shelved.

The EFF — formed by renegade members of the ruling African National Congress in 2013 — has shaken up the political landscape with its populist proposals to nationalise mines and banks and seize white-owned land without compensation.

The party’s programme has found fertile ground among the poor, who feel that only government fat cats and their cronies have enjoyed the benefits of democracy.

Around 25 percent of South Africans are unemployed, according to official statistics, while unofficial estimates put the figure much higher.

Efforts by church leaders to mediate and prevent a showdown at the traditionally glitzy ceremony to mark the opening of parliament appeared to have failed, with EFF whip Hlengiwe Maxon saying that Zuma would not be allowed to begin his address.

“He will not proceed until he has answered the questions,” she was quoted as saying in the local daily Business Day Wednesday. “No retreat, no surrender.”

For his part, Zuma told a gathering with editors Sunday that he had “never been nervous in my life” and would be directed by parliamentary speaker Baleka Mbete on how to respond if the EFF made good on its threats.

At the heart of the upheaval is Zuma’s refusal to accept an ombudsman’s decision that he should repay some of the public money spent on “security items” such as a swimming pool, amphitheatre, cattle pen and chicken run at his rural home in Nkandla in the eastern Kwazulu-Natal province.

The money spent on what were billed as upgrades would buy several luxury homes in Johannesburg or Cape Town.

Veteran columnist and political commentator Allister Sparks suggested Wednesday that the only way Zuma could defuse the looming confrontation would be to begin his address with acceptance of his responsibility for the overspending on his home and promise to repay some of the money.

“The whole nation would feel relieved and overjoyed. Cleansed. A heavy shadow of disillusionment and depression would be lifted. All would be forgiven,” he said.

“Unfortunately Zuma will almost certainly not do this.”

Whatever the outcome, parliament’s live television feed is likely to draw a huge audience Thursday — not so much to hear what Zuma has to say, as to see what happens.

But given that the transmission was controversially cut during the August debacle, there is no guarantee that viewers will see the whole drama play out.