Federal Nazi hunters say their efforts to investigate and expel World War II criminals are being obstructed by a group of more than 30 Eastern European emigre organizations that are raising legal defense funds for accused Nazis and openly urging their supporters not to cooperate with the Justice Department.

On Tuesday, the World Jewish Congress, after a year-long investigation, charged that various Baltic, Ukrainian and other Eastern European emigre groups have engaged in "an intensive and shocking campaign aimed at undermining the Justice Department's Nazi prosecution program."

On Thursday, Myron Wasylyk, director of the Washington office of the Ukrainian Congress Committee of America, responded by accusing the World Jewish Congress of "a vicious defamation campaign against Ukrainians, Balts and East Europeans" that has "served to promote the interests of the KGB," the Soviet secret police.

The World Jewish Congress report charged that the groups have been openly anti-Semitic in their native-language newspapers and have waged a campaign to set a statute of limitations on war crimes and to shut down the Justice Department's Office of Special Investigations (OSI), which is responsible for pursuing Nazi war criminals.

Current and former Justice Departmentattorneys say the report is accurate.

One OSI lawyer, who asked not to be identified, said, "Their efforts are to close us down. They have people who do nothing but monitor us, attack us. They are very active, and it's fraught with anti-Semitism."

Tony Mazeika, national coordinator for the Coalition for Constitutional Justice and Security, which claims at least 30 million emigre followers of Eastern European descent, charged that the WJC report is part of "an abusive campaign -- orchestrated by OSI -- that is absolutely criminal . . . . We have absolutely no animosity -- we want to work with Jewish groups in the United States."

One major complaint raised by the emigres is that U.S. prosecutors have used as evidence wartime documents provided by the Soviet Union.

Wasylyk, whose group represents more than 1 million Ukrainian Americans, said: "Most of the evidence OSI is using is supplied by the KGB. This is the issue as we see it. We're all for getting war criminals. But this is KGB-supplied evidence that's meant to defame Eastern Europeans, Balts and Ukrainians in the United States."

Wasylyk said U.S. emigre organizations have "obtained prominence . . . beyond what the KGB would like to see happen. We have new clout with Congress, the press and the Reagan administration. The KGB is starting this disinformation campaign to slander the Eastern European groups by claiming we're anti-Semitic."

OSI head Neal Sher said of the emigre groups: "Organizations and individuals have flooded each and every member of Congress, the White House, the State Department, the attorney general's office and the media . . . .

"It's ludicrous to say we're being duped by the KGB. That's a smokescreen to hide the fact that these people were involved in the most heinous of crimes . . . . If we're to pursue these cases, we have to go wherever the evidence is."

Many of the incidents of collaboration occurred in Latvia, Lithuania and the Ukraine, where anticommunist and anti-Semitic sentiment led some people to cooperate with the German occupation forces in the 1940s.

When Soviet evidence is used, Sher said, "We have requested the Soviets to produce the originals of documents to be used as evidence; they have done so. These documents are subjected to scientific testing, both by this government and, if so desired, independently by the defendant.

"When OSI attorneys and defense counsel travel to the Soviet Union to take testimony, Soviet prosecutors do not know in advance the questions that either side will ask. Nor do they know what documents or witnesses in the West are available to either corroborate or contradict the Soviet witnesses."

The emigre lobbying efforts have gone on for several years, according to both OSI and the emigre groups. But Eli Rosenbaum, a consultant to the World Jewish Congress and former Justice Department Nazi hunter, says it has escalated in the past six months, particularly since last month, when Mazeika's coalition was formally launched in Los Angeles.

But there is no indication that Justice is considering weakening the powers of OSI, which was created in 1979 to pursue Nazi war criminals living in the United States. Under U.S. law, former Nazis cannot be tried for their wartime crimes. Instead, they have been accused of violating immigration laws by lying about their Nazi pasts when they applied for U.S. citizenship. If convicted, they can be deported.

In the past two years, six former Nazis have been deported or left the country voluntarily.

In November 1983, several lawyers representing the emigre groups met with Justice Department lawyers -- including Stephen S. Trott, the assistant attorney general in charge of the criminal division -- to protest the use of Soviet evidence and push for a statute of limitations, jury trials and free court-appointed legal counsel for the defendants.

But Trott, who oversees OSI, made it clear in a followup letter that he opposes a statute of limitations and that the "Justice Department is committed in these cases to pursue evidence wherever the trail leads it." He added that U.S. immigration law does not provide for jury trials or free lawyers.

Some of the rhetoric of the emigre groups and their supporters has been openly anti-Semitic.

For example, a 12-page, single-spaced letter to Attorney General Edwin Meese III, signed by the Council of Latvian Officers Association of Australia and New Zealand, asks that the law creating OSI be overturned and adds, "Information is now available that no mass gassing of Jews and other prisoners took place at the Buchenwald and Dachau camps."

It goes on to say that one of the aims of Jewish organizations around the world is to "contaminate the judicial systems of the countries to serve their purpose . . . . It is well known that Jews are the most privileged ethnic group in the Soviet Union, although they deny it for political purposes."

Both Wasylyk and Mazeika say their groups are not anti-Semitic, but the foreign-language periodicals circulated by the emigre groups contain such phrases as "the Jewish Eichmanns," "Jewish Nazism" and "Jews who profited from the Holocaust."

The emigre groups have campaigned openly against OSI in the ethnic newspapers. For example, an article in the Sept. 23, 1983, issue of Darbininkas, a Brooklyn-based Lithuanian weekly, is entitled, "How to Defend Oneself from Attacks by OSI."

The newspapers are also used for fund-raising. Two prominent funds are the Fund for the Defense of Lithuanian Rights in Chicago and the Latvian Truth Fund in New York.

Aid has been solicited openly for accused criminals, including Han Lipschis, who had confessed to serving as an SS official at the Auschwitz-Birkenau camp in Poland. He has been deported to West Germany.

Rasa Razgaitis, a leader in an emigre group called Americans for Due Process, defended the fund-raising, saying that it is unfair to place the emigres on trial for a "civil technicality" and then send them to the Soviet Union, where they could be executed for their wartime activities. "These people are retired, old, they have limited funds and no right to court-appointed counsel," she said.

Israel Singer, executive director of the World Jewish Congress, said the emigre groups "fear that the Justice Department's prosecutions are exposing the American public to the historical fact that Hitler's annihilation of 6 million Jews was carried out not by the Germans alone, but rather with the extensive collaboration of Lithuanians, Latvians, Ukrainians, Estonians and other Europeans."