Athol Fugard's writing has helped to give a cultural voice to the black population of apartheid South Africa. It all started with a Greek tragedy, he tells Sara Keating.

Athol Fugard's diminutive stature and diffidence belies the heroic authorial presence that resonates throughout his plays. The soft cadences of his South-African accent, however, maintain a personal conviction in the powerful political impact that contemporary theatre can wield, and he defers with gracious modesty to the classical canon of ancient Greek tragedy as the shaping force of this belief, on both a personal and political level.

The story of Fugard's career is a circular one, which begins and ends with the great Greek tragedy, Oedipus Rex. From his stage debut at 24 years old to his most recent work, Fugard has been aware that he has been writing "at the feet of Greek tragedy, with its three magnificent unities of time, place and plot" shaping the genesis and form of much of his vast body of work.

In fact, Greek tragedy even provided the premise for his visit to Dublin, to participate in a panel discussion at TCD on the future of Greek tragedy in honour of his partner Marianne McDonald, a prolific classical scholar whose translations of ancient tragedy have earned her many international plaudits, including honorary Irish citizenship.

Fugard has written 29 plays, which have brought cultural visibility to the black population of apartheid South Africa. He has also written a collection of short stories, a collection of poetry, a family memoir, and two novels, the second of which, Tsotsi, was made into an Oscar-winning movie.

But ancient Greek tragedy might at first appear anomalous to the colonial and postcolonial context of Fugard's personal history and his highly politicised writing career. Born to an Afrikaaner mother and an English father, Fugard has spent most of his life in Port Elizabeth.

Following an English-language education in motor mechanics and philosophy, he hitchhiked his way up through Africa after dropping out of college, whereupon he signed up on a British steamer staffed by a mixed-raced crew which provided him with the formative experience of writing (a first novel that was subsequently thrown overboard) and his liberal anti-apartheid beliefs.

His personal history provides a context for understanding the political beliefs that have defined Fugard's writing. One of his first important plays, The Island, reflects this sense of a personal experience transformed into a political gesture, and sowed the seeds for his engagement with Greek tragedy.

IT WAS THE early 1960s and Fugard's first major play, Blood Knot, a drama about brothers of ambiguous racial heritage, had garnered him some local notoriety.

"One night I answered my door to four black men and a black woman who had come from the local ghetto area. They had come to ask me if I would help them start a drama group. It was an intimidating prospect because they were not college graduates. They were domestic servants, labourers, unemployed men. What they wanted was a voice, because the system had effectively silenced all opposition. This had the most profound effect on my life as a writer under the system of apartheid. There was censorship, banning orders, prison sentences for false charges . . . They wanted to talk about what was happening to them. They just wanted to be heard, even if it was only by their own people.

"My first instinct was to say 'no', but I said 'yes', and as we started working I tried to find a play through which these people could express their frustrations. And, well, all paths lead not to Rome, but to Athens. I gave them Antigone by Sophocles, and they embraced its image of the defiant voice with a passion that would have reduced you to tears. In the course of our rehearsals the actor who was playing Haemon, Sharkey, was arrested by the police - this would happen many times to the people that I worked with. He ended up on Robben Island, where Nelson Mandela was already in prison.

"He was so frustrated with not being able to finish our project that he persuaded another prisoner in his cell to put on a 15-minute version of Antigone as their contribution to the annual prison concert. What they focused on was the final confrontation between Creon and Antigone when he sends her to be walled up in the cave and she goes to the cave saying 'I go now to my living death because I honoured those things to which honour belonged.'

"I got letters smuggled back from Robben Island describing this and I was so struck by it that I immediately put it down into my notebooks. Some years later came a collaboration with two actors who had been walk-ons in our original production of Antigone. We took on Sharkey's story and created the circumstances of the final 15 minutes of their performance of Antigone. That was the play, and Sharkey was still on Robben Island."

Fugard continued to collaborate with black actors throughout the violent political instability of the 1970s and 1980s. This collaboration produced many plays and many important political moments in own life, such as the six-year confiscation of his passport where the government hoped that he would take an "exit visa" and leave the country; without a passport, he would never be able to return.

Fugard stayed, however, and, he continued to engage with issues of race, class and injustice that affected the people of his country, sometimes in a more biographical fashion, such as in Master Harold and the Boys, which toured Ireland in a Calypso production last year, or his most recent play, Entrances and Exits, which returns to the earliest story of his career in the theatre, Oedipus Rex.

In that defining moment of his stage debut, Fugard played the shepherd who reveals to Oedipus his true identity. Andre Huguenet, "the Laurence Olivier of the South African stage", played the tragic hero and a couple of years later Fugard met him "as an audience member in the last role of his life".

"After the performance I had an extraordinary evening with him in his dressing room, and we talked and clashed. He represented an old theatre of kings and cardinals, and I represented a new theatre where I was going to write about slums. But we reconciled and he spoke about the tragedy of the life. Three months later he committed suicide.

"That was 50 years ago, but my latest play is a memoir about that. It starts out with that climactic moment in Oedipus Rex when the shepherd tells Oedipus who he is, and it was only after the fact, when Marianne began probing me, that I realised that I had just put my Oedipus on the stage."

The more recent history of post-apartheid South Africa has wrought no changes in Fugard's commitment to giving the unrepresented people of South Africa a voice. Although he now lives for part of the year in California - where McDonald is professor of theatre and classics, and Fugard teaches playwrighting at the University of California, San Diego - he insists that South Africa will always be his home.

"It is all I've got as a writer. I can stand on a street corner in any city in South Africa and watch the life passing me and I can put together a plausible and potentially truthfully story for everyone I see: an old black woman rushing to catch to the bus in bare feet because she doesn't want to ruin her shoes; a businessman driving past in his BMW.

"I know them. If I ever lost that, I don't know what would happen, and both the old South Africa and the new South Africa give me plenty of stories to tell."

Tonight in Bewley's Café Theatre, however, Fugard has a different story to tell, an ancient Greek myth with a brand new ending. McDonald will read a condensed, poetic version of her own translation of Medea, and Fugard will take up where Euripides left off. It's not the first time they have worked creatively together in Ireland - her translation of Antigone, which he directed, was well received in Cork in 1999.

While McDonald will end her reading tonight with the key question of "whether Medea'scrime is really her glory", Fugard's short story will answer it with an imaginative excursion giving Jason a "just and exquisite moment of revenge" that reinforces the sense that, for Fugard, political victory and personal tragedy are indivisible.

Marianne McDonald and Athol Fugard will present Medea . . . The Beginning and Jason . . . The End tonight at 6.30pm at Bewley's Café Theatre (086-8784001). Admission is free but places are limited. Tsotsi is showing at the Screen, Dublin