Chancellor Helmut Kohl, in an emotional speech marking the 40th anniversary of the liberation of the Bergen-Belsen concentration camp, declared today that Germans bear a "never-ending shame" for the crimes and atrocities perpetrated during the Nazi era.

Speaking to a crowd estimated at 3,000 that included Jews who were inmates of the camp, Kohl said successive German generations must confront their historical responsibility by asking "why so many people remained apathetic, did not listen properly, closed their eyes to the realities when the despots-to-be solicited support for their inhumane program."

Bergen-Belsen, along with such death camps as Treblinka and Auschwitz where 6 million, Jews and others, perished in the Nazis' genocidal campaign, remains "a mark of Cain branded in the minds of our nation," Kohl said.

Standing in front of a memorial wall and obelisk that dominates a vast field of mass graves, Kohl proclaimed that "reconciliation with the survivors and descendants of victims is only possible if we accept our history as it really was, if we Germans acknowledge our shame."

The speech was Kohl's most impassioned atonement for the outrages of the Nazi regime since he became West Germany's leader in 1982. The contrite appeal seemed directed toward Jewish groups who have expressed fears that Kohl's efforts to depict himself as the country's first truly postwar leader was encouraging the notion that contemporary Germans should not be burdened by the Nazi past.

President Reagan, who is expected to visit Bergen-Belsen as well as a German military cemetery on May 5, sent a message to the ceremony to pay homage to the 64,000 inmates, including the diarist Anne Frank, who died in the camp.

"The Holocaust is part of the consciousness of responsible human beings everywhere, no matter what their age," Reagan said. "In a sense we are all its victims since it forces us to try to come to terms with a time when civilization lost its way."

Reagan's note was read by Robert Tynes, U.S. consul in Hamburg, acting on behalf of Ambassador Arthur Burns, who was delayed because of plane trouble.

Reagan's belated decision to stop at Bergen-Belsen during his official visit in West Germany May 1-6 was reached only after U.S. Jews and veterans groups voiced dismay that he intended to honor German war dead but to pass up an earlier proposal to commemorate those who died at the hands of the Nazis by visiting the Dachau concentration camp.

Reagan aggravated the furor over his plans to lay a wreath at the Bitburg military cemetery when he observed last week that the soldiers buried there, who include some Waffen-SS troops, were as much the victims of the Nazi regime as those who were killed in the camps.

Israeli President Chaim Herzog said in Tel Aviv, Reuter reported, that "President Reagan is one of the best friends we have, and we have the greatest admiration for him. We feel he's been ill-advised as far as visiting a cemetery in which the SS are buried."

Today, Kohl noted that "of the 6 million Soviet soldiers who were captured by the Germans as prisoners of war, far fewer than half survived. Hence, at this hour, we also reflect on the suffering inflicted in the name of Germany on the peoples of Central and Eastern Europe."

In calling the collapse of the Nazi dictatorship "a day of liberation for the Germans," Kohl expressed gratitude for the willingness of Germany's former enemies to seek a reconciliation based on democratic values after the war.

"We in the free part of Germany realize what it means, following Auschwitz and Treblinka, to have been taken back into the free western community," Kohl said.

"This was only possible because those nations -- and not least former concentration camp inmates and the relatives of victims of the Nazi dictatorship -- reached out their hands to us in reconciliation."

Kohl paid tribute to the long mutual relationship linking Germans and Jews and said he intended to promote the creation of "an archive for the study of Jewish history in Germany" that would trace Jewish contributions to German culture, music, business, and literature.

The towns of Bergen and Belsen, 25 miles north of Hanover, initially were used to incarcerate Soviet prisoners of war. About 50,000 Russians died there from starvation, disease and torture.

The POW zone was transformed into a concentration camp for Jews and other minorities in 1943. In the last months of the war, as the Soviet Army moved toward Berlin, inmates from camps in the eastern territories were rounded up and forced to retreat here on foot.

More than 30,000 Jews lost their lives at Bergen-Belsen during the two years that followed. Another 20,000 Gypsies, Italians, French, Danes and other Europeans died before British troops liberated the area on April 15, 1945. Even after that, more than 14,000 prisoners perished because they were so enfeebled by their ordeal.

Lola Fischel, a survivor from the camp who was 19 when she was taken there, recalled that the barracks were a sheer nightmare of "filth and pestilence." Typhoid and malaria were rampant. Some inmates, deprived of food and barely subsisting on putrid water, resorted to cannibalizing corpses to stay alive, she said.

Dov Zemanovich, who like many of the survivors attending the ceremony had flown in from Israel, said the camp commanders wanted to kill all remaining inmates in the final days by feeding them poisoned bread.

At a Jewish stone memorial where a prayer for the dead was recited, Zemanovich turned to Kohl and spoke as a representative of Bergen-Belsen survivors, imploring him to "stop anti-Semitism in its infancy" whenever it surfaces in West Germany.

He urged West Germany to pursue Josef Mengele, the Nazi doctor who mutilated thousands of victims. Zemanovich also insisted that West German leaders carried a special obligation to support Israel and its people.