Watching Yael Farber’s extraordinary relocation of Greek myth to a Truth and Reconciliation Commission hearing in South Africa was among the most difficult experiences I have ever had in the theatre. All the more reason to see it. This Farber Foundry production, first presented in association with Johannesburg’s Market Theatre, is harrowing almost beyond endurance. It is also potently, elementally theatrical, mesmerisingly ritualistic and deeply and uncompromisingly humane. Raw and unflinching, even as it horrifies, it demands attention.

Based mainly on Aeschylus’ Oresteia but drawing, too, on Sophocles, Farber’s production brilliantly translates the bloody cycle of vengeance in the House of Atreus to the atrocities of apartheid-era South Africa. The Chorus, who bear witness at the hearing, are played by the Ngqoko Cultural Group, made up of Xhosa tribeswomen (and one man), who create an unearthly soundscape around the action.

Calabashes and skin drums blend eerily with voices that soar, wail or groan gutturally. There are some straight-backed chairs and two tables. In the centre of the stage is a grave. Here Dorothy Ann Gould’s white farmer Klytemnestra, in grubby scarlet dress and dusty rubber boots, confronts her daughter Elektra (Jabulile Tshabalala). Molora means ash in Sesotho. Here, the ashes Elektra believes are the burnt body of her brother Orestes symbolise the razed remains of a ravaged nation. And they recall the pale powdery residue that fell over New York after September 11.

Farber shows with frightening ferocity where thirst for retribution can lead. Gould swings a pickaxe with a terrifying cry of bloodlust; her husband slain, desperate to find Orestes, she inflicts shocking acts of torture on the daughter whom earlier she held in a crushingly tight embrace. Sweating, unbalanced, her voice a low growl, she is without mercy, made almost bestial by rage. Tshabalala, at first a terrified child, then a humiliated yet dignified young woman, gradually and horrifyingly begins to turn into the very thing she hates. “You’ve become me. You choose the curse,” Gould’s Klytemnestra cautions.

It’s close to unbearable. Yet there’s also beauty here, as when Sandile Matsheni’s Orestes is reunited with his sister, or at the achingly hopeful conclusion when ashes fall silently upon the family, their fury perhaps stilled at last. This is art from the gut. I cannot recommend it highly enough.

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