DENVER--Australian Aboriginal actors depict a father's inability to provide for his family. Israeli players present the plight of an e'migre' who loses her husband because of his concern for their children's future. A Greek company winds down the ages from classical columns to a modern taverna in tracing a woman's efforts to locate the father of her child.

Does anything hammer home more convincingly the universality of man than a concentrated fare of international drama? To the proven boundary-smashing of films and TV, add the immediacy of live drama, and even the least imaginative can't help glimpsing how alike are the basic, lasting strains of humanity.

With the Rocky Mountains as its backdrop, this vibrant city has just presented its first "World Theater Festival" in the Denver Center. In 24 days there were 13 countries represented in 114 performances. It's so expensive a concept that unless participating nations paid a major part of the transportation bills, costs would be even more staggering. As it is, a "first" does not necessarily guarantee a second.

Among the highlights this year: Britain's National Theater presented "The Mayor of Zalamea," by Spain's Calderon de la Barca. His theme is varying conceptions of honor. Theatremanufaktur of Berlin staged a modern play by Pablo Neruda, "Murieta," whose ghost, the playwright claims, still rides in California.

There was Canada's "Billy Bishop Goes to War," which had vast success last year at Arena Stage, and Yugoslavia's Zagreb Theater Company in Dusan Jovanovic's "The Liberation of Skopje," which will appear in Washington Aug. 19 through 28 sponsored by Source Theatre.

Through all the plays and novelties--Philippe Petit doing his acrobatics atop the glass roof of the center's Galleria and Footsbarn Theater, a much-traveled group from Cornwall playing an old English Mummer's Favorite in a tent--ran the thread of universal similarities, family life, honor, superstitions and greed.

Most sophisticated of the Denver ventures, indeed a journey into art, was the 7-year-old Amphi-Theatre of Greece, which created a highly amusing treatment for one of its classical comic writers, Menander. The group covered two millennia tracing his farce, "The Arbitration," from how it might first have been performed in masks to how it might have ended, Greek movie fashion, in a taverna battle of chair-throwing and passionate reconciliation. Between came deft illustration of how the story might have progressed through commedia dell'arte, Molie re and Victorian England. The major character is a courtesan played by an actress (Ilias Lambridou) who, with red dress, spike heels and eye-flapping blond hair, resembles Melina Mercouri, the current minister of culture, a coincidence not lost on the appreciative audience.

The emotional pull of this production was supplied by a creative device of director Spyros A. Evangelatos. Between each of the interludes came a procession of three women with a cart. In pure mime they indicated they were traveling players of the ages, telling us, without words, how the players struggle onward with humanity's timeless lessons. The women's measured progress, superbly led by Leda Tassopoulou, was a marvelous illumination. The audience rightly awarded it cheering ovations.

Israel's "Medea" was lean and disciplined. The Habimah company is its nation's subsidized national theater, established in Moscow in 1918, removed to Tel Aviv in '45 and finally sanctioned by the state 24 years ago. It is a universally respected group.

Though this version of Euripides included further variations from Seneca, Robinson Jeffers "and others," its running time was surprisingly brief, little more than an hour. The tone was controlled, reasonable, cerebral; the setting was of white panels, some plexiglass and a rocking chair for the leading woman of the chorus of two.

The production may have been hampered by an accident to the announced Medea, Miriam Zohar, on her way to Denver, but surely her replacement by Joanna Peled, a company member who had never tackled the role, was in the same key. Tall, red-haired, statuesque, Peled has theatrical presence, but she carefully conserved passion for the final scene with Jason and their children, a vastly different approach from Zoe Caldwell's Tony-winning dynamics.

Habimah's sternly controlled style was strikingly exemplified by the splendidly spoken Nurse of Shoshana Duer, whose vocal command reminded one yet again that knowledge of a language (Hebrew, in this instance) is rarely vital to a performance by quality actors.

Unquestionably, the audience reaction was tempered by the version's brevity as well as the news from Beirut. Nothing could better illustrate the cultural differences between the European (Ashkenazi) and Oriental (Sephardi) branches of Judaism. This "Medea" is pure Ashkenazi, its control wholly at variance with the events in Lebanon.

Fascinating is the word for the Australian Aboriginal Theater's "The Cake Man," performed in the center's 200-seat Lab of modest pretensions. The plight of the black Aborigine in Australian culture suggests American treatment of its imported blacks, but even more the attitudes toward the native Indian.

This play by Robert J. Merritt, written while he was in jail for a minor infraction, dramatically depicts the Aboriginal frustrations and inability to crack through to a decent chance at life. The first scene serves as a symbol, showing how the whites--represented here by a priest, a soldier and a commercial settler--treat an Aboriginal family as savages. With implied concurrence from the others, the soldier kills the father.

Some years later we are with another, similar family. The child delights in an old folk tale about a stranger who gives a cake to children, as the settler had done in the first scene. The mother takes comfort in her Bible. The father, unable to earn an honorable living, bursts with rage at his birthright of injustices.

Born in 1945, the ninth child in a laborer's family, playwright Merritt was brought up in the Christian Erambie Aboriginal Mission, which, he states, has not changed since his boyhood.

His play's distinction lies in its refusal to draw outright villains. Instead, Merritt shows the ignorance of those who fail to understand the Aboriginal civilization. In several eloquent speeches by the father, spoken arias of poetic tone, he distills the original Australian's outrage. After the spirited little boy has received an unexpected cake from a white neighbor, the father refers to the two realities he has learned: what the settlers have taught and his own scorned inheritance:

"There are two realities," he says, "two realities . . . An' I've lost one. But I want it back . . . I need it back . . . Not yours . . . Mine."

Again, the audience reaction was expressive. Justine Saunders' assured performance as the mother stems from considerable acting skills. She, Brian Syron (as the father) and Merritt can return to their base in Sydney with a sense of achievement over their first American adventure.

In sum, these plays should be viewed less as individual works than as a whole. Their themes are related. Their insights are timeless and without boundaries.

The idea of world theater festivals began, of course, with the Greeks. But they rarely last long. Paris continues its annual festival, perhaps through geographical convenience. Peter Daubney's admirable London festivals lapse into irregularity, unquestionably through fiscal inconveniences. Baltimore staged a festival last summer, at a considerable loss to the guarantors.

But financial losses are inherent in the concept. Only a committed leadership can take on so defiantly profitless a venture. That the Denver Center for the Performing Arts--concurrently presenting James Galway and his flute at one end of its Galleria and "A Chorus Line" at the other--could assemble this World Theater Festival reveals it as one of the nation's most imaginative. Center chairman Donald R. Seawell has grasped both the rose and the nettle of this ideal. While the nettle must pain, the rose is beautiful.