"The Foreign Ministry actively supported all measures of persecution, rights deprivation, expulsions and the Holocaust," Eckart Conze, one of four historians asked to shed light on the ministry's role in the Holocaust, told the weekly Frankfurter Allgemeine Sonntagszeitung.
"The Foreign Ministry was a criminal organisation," he told Der Spiegel magazine.
Historians investigating the ministry's role found documents in which the official in charge of Jews, Franz Rademacher, justified why he had to travel on an official mission to Belgrade.
"Liquidation of Jews in Belgrade and talks with Hungarian envoys in Budapest," read one paper. Conze called the revelations "shocking."
The historians' report which was commissioned by then Foreign Minister Joschka Fischer in 2005 is to be officially published next week. "I read the report and was more and more horrified," Fischer told the FAS.
Holocaust survivors on Sunday welcomed the report's findings.
The American Gathering of Holocaust Survivors and their Descendants hailed the report as shedding light on a chapter that had remained shrouded in secrecy more than six decades on.
"Germany has taken an honest and painful look at its past," Elan Steinberg, vice president of the New York-based organisation, said in a statement.
"Previous efforts to whitewash the role of the Foreign Ministry and its personnel in the crimes of the Holocaust are now categorically refuted. This report is a pointed reminder of the broad cross-section of German society and institutions which were implicated in the Holocaust and the brutalities of the Nazi regime."
Conze said previous claims Nazi Germany's diplomats played ittle active part in the deportation and mass extermination of European Jews were patently false.
The 880-page report entitled "The Office and the Past" was written by Conze and fellow German Norbert Frei, Peter Hayes of the United States and Israeli Moshe Zimmermann.
The research found that post-war chancellor Konrad Adenauer, who also served as foreign minister from 1951 to 1955, kept many of the Nazi diplomats involved in the Holocaust on staff.
Der Spiegel said the envoys were often sent to Arab countries or Latin America, where public protest over their past was less likely.
In 1966, Social Democratic Foreign Minister Willy Brandt, who would later become chancellor, maintained Ernst Achenbach as a top diplomat despite his involvement in the Holocaust.
Achenbach had been a high-ranking staff member at the German embassy in Paris and was "actively involved in deportations", the historians said. He managed to block until 1974 an agreement with Paris allowing Nazis who had committed crimes in France to be prosecuted.
The cover-up continued at least into the 1980s, when the ministry declined to hand over damaging documents from the Third Reich to researchers.
Der Spiegel noted the internal resistance to a thorough reckoning at the
ministry had continued even when Fischer ordered the report five years ago.
It said current Foreign Minister Guido Westerwelle would have the report included in the syllabus for diplomatic training and have embassy brochures rewritten if they propagated "myths" about the Nazi-era foreign service.