WASHINGTON (AP) _ Kurt Waldheim, the former U.N. Secretary-General, purposely hid the fact that he worked for two German generals who were convicted of World War II war crimes, the Simon Wiesenthal Center for Holocaust Studies says.

Waldheim worked on the staffs of Alexander von Loehr and a second general named Friederich von Stahl, Rabbi Marvin Hier, dean of the Los Angeles center, said Tuesday. Both generals were hanged for atrocities committed in the Balkans.

Waldheim's ambitions as ''a budding world-class diplomat'' would have been harmed if he was linked to the two generals, Hier said.

''The center believes that Waldheim concealed his past not only because he did not want people to know where he was during that period, but also because he did not want people to know for whom he was working,'' said Hier.

Previewing testimony to the House Foreign Affairs subcommittee on human rights, Hier said the Wiesenthal Center, named for Nazi hunter Simon Wiesenthal, undertook its own investigations in Europe after the World Jewish Congress alleged that Waldheim was involved in war crimes between 1942 and 1945.

Waldheim, 67, U.N. secretary-general from 1972-82, is a candidate for president of Austria. He has denied charges that he was involved in Nazi atrocities during the war and has described himself as the victim of a smear campaign.

The center has not taken a position on Waldheim's personal participation or non-participation in such activities, the rabbi said, stressing instead findings that in his autobiography and elsewhere Waldheim sought to conceal his past.

The center also has evidence that Waldheim's 1944 doctoral thesis at the University of Vienna was a laudatory work discussing the ''Reichsideen (imperial theories)'' of German philosopher Konstantin Frantz, described by Hier as ''a notorious 19th century anti-Semite who believed one way or another that the Jewish question would have to be solved, either, as he put it, by chopping off the head of every Jew ... or by driving the lot out to Palestine.''

''Although Waldheim is careful not to cite any of the anti-Semitic references of Konstantin Frantz, his dissertation extols and endorses Frantz's 'Greater Reich' concept which sees Austria and other European countries absorbed by Germany...'' Hier said.

This was at odds with statements in Waldheim's autobiography maintaining that he opposed Hitler's ''Anschluss'' taking over Austria, he added.

The rabbi said the thinking of Waldheim was revealed by the closing passage of his thesis, for which he selected a quotation ''from another notorious German anti-Semite,'' Friedrich Gentz: 'Europe is durch Deutschland gefallen, durch Deutschland muss es wieder auferstehen. (Europe fell through Germany, through Germany it must rise again)'.''

Hier questioned why Waldheim found it necessary to write a pro-greater Germany thesis when of the 37 dissertations presented that year only 11 were connected with Nazism and the others were on neutral subjects.

''Konstantin Frantz's ideas hardly befit the image of an anti-Nazi which Waldheim so carefully cultivates about himself in his autobiographies,'' he said.

Another unanswered question, Hier said, is why Waldheim's thesis is not on an authoritative listing of 1944 dissertations submitted at the University of Vienna, and why it was placed in the university archives only in the late 1960s or early 70s.

''Apparently it was held somewhere else,'' concealed from the public, which after the war was in an anti-Nazi mood, Hier said.

Waldheim would have been 35 when he wrote the thesis.