After some hesitation and with considerable anxiety, Israelis sat down in front of television sets Monday night and confronted an event many would like to put behind them - the Holocaust.

What was believed to be one of the largest audiences in the country's history - an estimated 1.5 million of Israel's 3 million people - watched the first two-hour 20-minute segment of the protrayal of events that culminated in the death of millions of Europe's Jews under the Nazis.

In four sequences this week and next the Hollywood docu-drama portraving those haunting events is being shown in a country which in some measure exists becaue they happened.

Until now, Israel has paid surprisingly little attention to the subject. One day a year is observed as Holocaust Day, and occasional trips are organized to the Yad Vashem memorial, but, with the exception of such events as the Eichmann trial, the sensitive issues has been largely confined to the tortured memories of the approximately 400,000 survivors living here.

The memories harbored by those 400,000 and the scars they bear were debated sharply within Israel's state broadcasting authority before it was finally decided to broadcast the show.

Yitzhak Livni, director of the television service, said he made the decision to run the program, despite some sections that are "more or less banal, a soap opera," because it is a "serious work in television terms" - an attempt to focus a medium of great power on a subject that often defies human understanding.

Shmuel Ron, a social worker who was active in the resistance movement in Poland, saw the strengths and weaknesses of the show in much the same way as Livni. When he saw the first two segments during a visit to the United States last spring, he at first felt the portrayal was "too sweet and nice."

Then Ron said, he began to realize that the "movie isn't being shown for me, but for others to whom I couldn't and didn't trust myself to talk to about it."

For all the dangers for survivors and for the national psyche, Ron believes the movie has a powerful message for Israelis.

"It serves as a warning system against too much dependency," he says. "Although Jews today are safe in the U.S., historical development does not guarantee that the past won't return. No more voices are heard today about what's happening (to Christians) in Lebanon than was heard about Jews in 1938 and '39".

Nevertheless, there are those for whom such a show will be a traumatic experience, and Israeli psychiatrists and other professionals are preparing to deal with it.

Dr. Hillel Klein, director of a government psychiatric hospital near Jerusalem, has urged that a period of commentary and discussion follow each segment of the program to lessen its impact. The broadcast authority, however, has decided to wait until a week after the program is completed before running a special discussion program.

Dr. Klein, himself a survivor of the concentration camps, has been invovled in research comparing American and Israeli children of survivors of the holocaust. His findings show that the children of survivors in New York are much more traumatized than their Israeli counterparts in Jerusalem, are more alienated from their parents by the generation gap, and avoid to a greater extent their parents' experience. Part of the difference stems, he believes, from the inability of the second generation in America to discuss their feelings about their parents' past.

For Israelis, Klein believes there is another factor that lies behind the reluctance so far to address the holocaust question, except in a ritualistic way on "Holocaust Day." There has been a fear," he said, "because of fear of damaging the image of the Israeli fighter."

Klein does not recommend that everyone in Israel tune in to this controversial series. Those who do, however, he said, "should see it as a family, discuss it and ventilate their emotions."

Sima Zonder, 46, Polish-born daughter of the Holocaust, is one of the those torn between fear of the pain many may suffer and realization that a generation of young Israelis has little understanding of the events that played such a traumatic role in the lives of the generations before them.

"I personally can't watch it," she said recently. "I shrivel up inside if I read a book or see a movie on the subject."

She conceded, however, that "the whole world should see it, especially because there have been recent publications in the world denying that the Holocaust ever took place."

"Young Israelis don't appreciate what we went through," she said. "They say the Jews should have stood up. They should see that we simply couldn't stand up against Hitler, Hitler can spring up again."