The Justice Department yesterday moved to strip the citizenship of a 31-year resident of Queens, N.Y., alleging that he took part in the executions of Ukrainian Jews during World War II.

In a suit filed in U.S. District Court in Brooklyn, the Justice Department's Office of Special Investigations charged that Michael Dercacz, 71, of Astoria, N.Y., should lose his American citizenship because he concealed his service in the Nazi-controlled Ukrainian Police Command when he entered the United States as a displaced person in 1949 and when he became a U.S. Citizen in 1954.

Justice Department sources said yesterday's move to revoke his citizenship was a necessary legal step toward deportation proceedings against Dercacz. U.S. law states that a citizen cannot be deported.

In the suit filed yesterday, the Justice Department identified Dercacz as a member of the Ukrainian Auxiliary Police "who systematically participated in the execution of Ukrainian Jews." The suit stated that Dercacz was a member of the Ukrainian Auxiliary Police from September 1941 to August 1943 in Jaryzow-Nowy, an area in the Ukraine occupied in that 23-month period by the Nazis.

"The defendant personally assisted the German forces in the persecution of the civil population because of their race and religion," the suit states. "He guarded, beat and killed unarmed Jewish civilians."

Nowhere does the suit mention how many Jews Dercacz is alleged to have executed. Hundreds of thousands of Ukrainian Jews were put to death by the Nazis, including more than 100,000 slaughtered at Babi Yar in 1943.

While the suit only identifies Dercacz as a "uniformed" member of the Ukrainian Auxiliary Police, he was identified in 1979 by Nazi-hunter Simon Wiesenthal as the former deputy chief of the Ukrainian Police.

At that time, Wiesenthal's Documentation Center in Vienna formally asked the Israeli Police and West Germany's Central Office for the Persecution of Nazi Crimes "to look for witnesses and evidence against this man."

The suit against Dercacz claims he lied about his past when he came into the United States from West Germany in 1949 as a displaced person. The suit said Dercacz said he had been a farmer in the Ukraine.

"The defendent willfully misrepresented and concealed his service," the suit states. "His entry into the U.S. [under the Displaced Persons Act of 1948] was unlawful, he never established lawful residence in the U.S."

The move against Dercacz is the second in two months by the Justice Department's Office of Special Investigations, which was set up in May 1979 in part to hunt down former Nazi war criminals. The office has been given more than 200 leads on ex-Nazis now said to be living illegally in the United States and has asked Congress for $2.3 million to follow up the leads.

In moving to strip Dercacz of his citizenship, the Justice Department would say only that it had identified his service in the Ukrainian Auxiliary Police from "official records and eyewitness statements." Sources at Justice would not go into details of hows and where it found the records or the eyewitnesses.